FUEL INJECTION CIRCUIT WITH SELECTABLE PEAK INJECTION CURRENTS

• US 20070278323A1
• Filed: 05/31/2007
• Published: 12/06/2007
• Est. Priority Date: 06/01/2006
• Status: Active Grant

• Current Assignee: Vitesco Technologies USA, LLC (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Morenilla, Luis Juan, Stafford, James Joseph, Markow, Paul Aaron
• Granted Patent: US 7,789,072 B2
• Time in Patent Office: Days
• US Class Current: 239/92
• CPC Class Codes: F02D 41/20 Output circuits, e.g. for controlling currents in command coils
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements

Abstract

A charging circuit for a fuel injection coil enables the controller to selectively add a pulse of increased amplitude to the beginning of an injection current pulse. Optionally, the controller can also select one of a plurality of amplitudes for the pulse and control the duration of the pulse.

Claims

1. A method for charging a fuel injection coil including the steps of:

charging an injector coil at a first level for a first period of time; and

charging the injection coil at a second level lower than the first level for a second period of time subsequent to the first period of time.

2. The method of claim 1 wherein the second period of time is contiguous with the first period of time.

3. The method of claim 2 further including the step of comparing a level of the coil with a reference and increasing the level of the coil based upon the comparison

4. The method of claim 3 further including the step of decreasing the reference from the first time period to the second time period.

5. The method of claim 4 further including the step of selecting the level of the reference from among a plurality of predetermined available levels during the first time period.

6. The method of claim 5 further including the step of selectively activating combinations of a plurality of switches to select the level of the reference.

7. The method of claim 5 further including the step of selectively altering a resistance in a voltage divider to select the level of the reference.

8. The method of claim 1 further including the step of selectively extending the first period of time.

9. The method of claim 1 further including the step of determining that the injector coil is faulty based upon a charging time of the injector coil when the injector coil is charged at the first level.

10. A charging circuit for a fuel injector coil comprising:

a driver for selectively charging the coil based upon a reference value; and

a timer for altering the reference value for a first period of time, such that the driver charges the coil at a higher level during the first period of time.

11. The charging circuit of claim 10 wherein the driver includes a comparator that compares a charged level of the coil to the reference value.

12. The charging circuit of claim 10 wherein the timer generates a pulse for the first period of time.

13. The charging circuit of claim 10 wherein the reference value is determined based upon states of a plurality of switches.

14. The charging circuit of claim 13 wherein the plurality of switches are a plurality of transistors.

15. The charging circuit of claim 13 further including a plurality of resistors, each associated with one of the plurality of switches, and wherein each switch selectively places one of a plurality of resistors in a voltage divider to alter the reference value.

16. The charging circuit of claim 10 further including a bad coil detection circuit including a timing device for determining a time required for the coil to reach a first level of charge, the bad coil detection circuit selectively alterable to accommodate detection of a bad coil when the reference value is selectively altered for the first period of time.

17. The charging circuit of claim 16 wherein the timing device reduces the time permitted for the coil to reach the first level of charge when the reference value is selectively altered for the first period of time.

18. A charging circuit for a fuel injector coil comprising:

a driver for selectively charging the coil at a normal level or at a higher level; and

a timer generating a pulse for a first period of time, the driver charging the coil at the higher level based upon the pulse and returning to the normal level after the pulse.

19. The charging circuit of claim 18 wherein the driver includes a comparator that

compares a charged level of the coil to a reference value, and wherein the pulse alters

the reference value for the first period of time.

20. The charging circuit of claim 19 further at least one switch for selectively altering the

higher level at which the driver selectively charges the coil.