End of valve motion detection for a spool control valve

• US 6,866,204 B2
• Filed: 04/04/2002
• Issued: 03/15/2005
• Est. Priority Date: 04/10/2001
• Status: Expired due to Fees

• Current Assignee: Continental Automotive Systems, Inc. (Continental AG)
• Original Assignee: Siemens VDO Automotive Corporation (Siemens AG)
• Inventors: Becker, Joerg Christoph, Hammer, Guenter
• Primary Examiner(s): Nguyen, Dinh Q.
• Application Number:
  US10/116,207
• Publication Number:
  US 20020145054A1
• Time in Patent Office: 1,076 Days
• Field of Search: 239 88- 96, 239/124, 239/5, 123/446, 123/447, 123/508, 123/507, 137/554
• US Class Current: 239/5
• CPC Class Codes: F02D 2041/2055 with means for determining actual opening or closing time
• CPC Class Codes: F02D 41/401 Controlling injection timing F02D41/402 takes precedence
• CPC Class Codes: F02M 57/025 hydraulic, e.g. with pressure amplification
• CPC Class Codes: F02M 65/00 Testing fuel-injection apparatus, e.g. testing injection timing testing of ignition F02P17/00; measuring fuel consumption G01F9/00; Cleaning of fuel-injection apparatus
• CPC Class Codes: F02M 65/005 Measuring or detecting injection-valve lift, e.g. to determine injection timing
• CPC Class Codes: Y02T 10/40 Engine management systems
• CPC Class Codes: Y10T 137/8242 Electrical

Abstract

A fuel injector system (10) includes a piezoelectric sensor (52) mounted along a spool valve axis (18) of the injector body (12). The piezoelectric sensor (52) is mounted within a spool valve stop (41). As the spool valve (16) reaches the stop (41), the piezoelectric sensor (52) identifies the force exerted thereupon and transmits the generated signal to the controller (44). Through communication with piezoelectric sensor (52) the controller determines when the spool valve (16) has reached a predetermined position.

Claims

1. A method of injecting fuel comprising the steps of:

(1) providing a fuel to a spool valve movable between a first and a second coil such that the spool valve selectively provides fuel flow to a fuel injector when the spool valve is located in a first position and prevents fuel flow to the fuel injector in a second position;

(2) locating a piezoelectric sensor adjacent the spool valve;

(3) measuring a signal generated by the piezoelectric sensor;

(4) determining a predetermined position of the spool valve in response to said step (3); and

(5) locating a measurement window within a time period defined between a first command signal and a second command signal.

2. A method as recited in claim 1, wherein said step (3) is performed within a predetermined timing window.

3. A method as recited in claim 1, wherein the signal is a voltage.

4. A method as recited in claim 1, further comprising the step of locating the piezoelectric sensor within a stop adjacent the spool valve.

5. A method as recited in claim 1, further comprising the step of:

identifying a signal from the piezoelectric sensor in response to contact between the spool valve and the piezoelectric sensor.

6. A method as recited in claim 5, further comprising the step of:

determining whether the signal from the piezoelectric sensor is within the measurement window.

7. A method as recited in claim 1, wherein said step (2) comprises

moving the spool valve along a spool valve axis to selectively contact the piezoelectric sensor.