Sparkplug having variable spark gap and ignition device for the same

Patent metadata

Field	Value
Publication number	US-9793688-B2
Application number	US-201514944290-A
Country	US
Kind code	B2
Filing date	Nov 18, 2015
Priority date	Nov 18, 2015
Publication date	Oct 17, 2017
Grant date	Oct 17, 2017

Abstract

A center electrode is electrically coupled with a main terminal. A ground electrode is opposed to the center electrode to form a gap therebetween. A piezo actuator changes in length on application of a voltage. The piezo actuator actuates one of the center electrode and the ground electrode to manipulate the gap.

First claim

What is claimed is:

1. A sparkplug comprising:
a main terminal;
a center electrode electrically coupled with the main terminal;
a ground electrode opposed to the center electrode to form a gap therebetween; and
a piezo actuator configured to change in length on application of a voltage, wherein
the piezo actuator is configured to actuate one of the center electrode and the ground electrode to manipulate the gap.

2. The sparkplug of claim 1 , wherein
the piezo actuator is configured to increase the gap to expand an electric spark when the gap forms the electric spark on voltage application.

3. The sparkplug of claim 2 , wherein
the piezo actuator is configured to decrease the gap into an original form on release of the voltage application.

4. The sparkplug of claim 1 , wherein
the piezo actuator is electrically coupled with the main terminal and the ground electrode in series.

5. The sparkplug of claim 1 , wherein
the piezo actuator is electrically coupled with the main terminal and the ground electrode in parallel.

6. The sparkplug of claim 1 , wherein
the piezo actuator is affixed to the center electrode and is configured to actuate the center electrode.

7. The sparkplug of claim 6 , further comprising:
a housing integrated with the ground electrode, wherein
the housing surrounds the center electrode, and
the center electrode is movable relative to the housing.

8. The sparkplug of claim 6 , wherein
the piezo actuator is located between the main terminal and the center electrode.

9. The sparkplug of claim 8 , wherein
the piezo actuator includes internal electrodes and an internal conductor,
the internal electrodes are electrically coupled with the main terminal and the center electrode, respectively, and
the internal conductor electrically couples the internal electrodes therebetween.

10. The sparkplug of claim 1 , wherein
the piezo actuator is affixed to the ground electrode and is configured to actuate the ground electrode.

11. The sparkplug of claim 10 further comprising:
a housing surrounding the center electrode, and
the piezo actuator is located between the ground electrode and the housing.

12. The sparkplug of claim 11 , wherein
the piezo actuator includes internal electrodes and an internal conductor,
the internal electrodes are electrically coupled with the ground electrode and the housing, respectively, and
the internal conductor electrically couples the internal electrodes therebetween.

13. An ignition coil device comprising:
a primary coil;
a secondary coil magnetically coupled with the primary coil to boost primary voltage in the primary coil into a secondary voltage;
a sparkplug electrically connected with the secondary coil to receive application of the secondary voltage;
an igniter switch configured to cause a primary current in the primary coil to generate the primary voltage in the primary coil; and
a piezo switch electrically connected with the sparkplug, wherein
the sparkplug includes:
a center electrode and a ground electrode forming a gap therebetween; and
a piezo actuator configured to actuate one of the center electrode and the ground electrode to manipulate the gap, wherein
the piezo switch is configured to apply voltage on the piezo actuator independently from the igniter switch.

14. The ignition coil device of claim 13 , wherein
the sparkplug has a main electrode electrically coupled with the center electrode, and
the sparkplug has a piezo terminal connected with the piezo switch.

Assignees

• Denso Int America Inc

Inventors

• Friery Blaise
• Polcyn Nicholas
• Lee Nicholas

Classifications

• H01T15/00

  Circuits specially adapted for spark gaps, e.g. ignition circuits (ignition circuits for internal-combustion engines F02P; electric spark ignition for combustion apparatus F23Q; protection circuits using spark gaps H02H9/06) · CPC title

• H01T13/26 Primary

  for adjusting spark gap otherwise than by bending of electrode · CPC title

• F02P15/00

  Electric spark ignition having characteristics not provided for in, or of interest apart from, groups F02P1/00 - F02P13/00 {and combined with layout of ignition circuits (not combined F02B, F02C, F02G, F02K)} · CPC title

• F02P3/0442

  using digital techniques (F02P3/0456, F02P3/053, F02P3/0554, F02P3/0558 take precedence) · CPC title