Combination igniter and sensor for an internal combustion engine
An igniter for an internal combustion engine, the igniter comprising: a center electrode; an insulator disposed about the center electrode; a ground shield disposed about the insulator, the insulator having a tip portion extending past an end portion of the ground shield and a tip portion of the center electrode extending through and away from the tip portion of the insulator; and a spark gap disposed between the tip portion of the center electrode and the end portion of the ground shield.
1. In combination an igniter and a sensor for an internal combustion engine, comprising:
a center electrode;
an insulator disposed about the center electrode;
a ground shield disposed about the insulator, the ground shield terminating at an end portion, the insulator having a portion extending past the end portion of the ground shield, wherein the portion of the insulator extending past the end portion of the ground shield terminates at a tip portion, and a portion of the center electrode extends through the insulator and terminates with an electrode tip portion that extends from the tip portion of the insulator;
an ion sensing portion located on the electrode tip portion; and
wherein a spark gap is defined between a peripheral edge of the ion sensing portion and the end portion of the ground shield.
2. The igniter as in claim 1 , wherein the spark gap extends along an outer periphery of the portion of the insulator that extends past the end portion of the ground shield.
3. The igniter as in claim 1 , wherein the spark gap has a frusto conical shape diverging from the tip portion of the insulator to the end portion of the ground shield.
4. The igniter as in claim 2 , wherein the outer periphery of the portion of the insulator decreases in dimension as is extends from the end portion of the ground shield.
5. The igniter as in claim 1 , wherein the ground shield is formed from one of a nickel alloy and a stainless steel alloy.
6. The igniter as in claim 1 , wherein the ion sensing portion is an annular disc portion disposed about the tip portion of the center electrode.
7. The igniter as in claim 6 , wherein the spark gap extends between an outer periphery of the annular disc portion and the end portion of the ground shield.
8. The igniter as in claim 7 , wherein the spark gap extends along an outer periphery of the portion of the insulator that extends past the end portion of the ground shield.
9. The igniter as in claim 1 , wherein the end portion of the ground shield is configured to have a frustoconical portion converging toward an outer periphery of the portion of the insulator extending past the end portion of the ground shield and the ground shield has an outer diameter substantially in the range between 6 millimeters and 8 millimeters.
10. The igniter as in claim 1 , wherein a distance between the electrode tip portion of the center electrode and the end portion of the ground shield is substantially in the range between 1.7 millimeters and 10 millimeters.
11. The igniter as in claim 1 , wherein the ground shield has an outer diameter substantially in the range between 6 millimeters and 10 millimeters.
12. In combination an igniter and a sensor for an internal combustion engine, comprising:
a center electrode;
an insulator disposed about the center electrode;
a ground shield disposed about the insulator, the ground shield terminating at an end portion, the insulator having a first portion located within the ground shield in a facing spaced relationship and a second portion extending past the end portion of the ground shield the second portion of the insulator terminating at a tip portion, and a portion of the center electrode is surrounded by the insulator and has an electrode tip portion that extends from the tip portion of the insulator;
an ion sensing portion located on the electrode tip portion; and
wherein a spark gap is defined between a peripheral edge of the ion sensing portion and the end portion of the ground shield.