Spark Plug Characteristics2018-07-24T07:18:19+00:00

Spark Plug Characteristics

Standard Plug

(Example) BKR5ES-11

– Standard type of spark plug.

V-grooved center electrode spark plug

(Example) BKR5E-11

– Grooving is done at 90°for the center electrode and thus sparks are easily discharged.
– Since the sparks are discharged at near the periphery of the center electrode, there is less qeunching action of the electrode, and ignition performance is enhanced. Therefore, it is effective during engine start-up, idling and acceleration.

Platinum plug (Long life type)

(Example) PFR5G-11

-Platinum alloy is used in the center electrode. Moreover, platinum alloy is used in discharge part of the ground electrode. This is the high performance and long life plug.

Iridium plug (Long life type)

(Example) ILTR6A-13G

-Iridium alloy is used in the center electrode. Moreover, platinum alloy is used in discharge part of the ground electrode. This is the high performance and long life plug.

High ignitability nickel plug

(Example) LR7D

-The diameter of the center electrode tip is made thinner and the ground electrode is made oval shaped. Thus the flame quenching effect is reduced and ignitability is improved.


(Example) SILZKAR7B11

– Compared to the conventional plugs, the ground electrode is shortened to reduce its overlap onto the center electrode, thereby reducing the flame quenching effect and futher enhancing the ignitability. It provides for excellent breakage countermeasures by suppressing overheating of the ground electrode. This is the high preformance and long life plug which gives stable combustion with no abnomal combustion even in high compression engines.


(Example) SIFR6A

– With a small diameter center electrode and the taper-cut design of the ground electrode, the sparks are concentrated on the tip and the flame quenching effect is suppressed. To futher ensure durability, thin square platinum alloy is welded to the ground electrode.

DFE plug (Double fine electrode)

(Example) DILKAR7B11

– Iridium alloy is used at the tip of the center electrode and fine wire platinum alloy is welded on the ground electrode. This design achieves a high performance and long life.

3-ground electrode hybrid type

(Example) PZFR5N-11T

– Normally sparks discharge between main electrodes. When there is carbon fouling, sparks discharge between the side electrode and the center electrode, burning our the carbon deposits on the insulator.

Multi-ground electrode plug

(Example) BKR6EK – 2 ground electrode plug
(Example) BKUR6ET – 3 ground electrode plug
(Example) BKR6EQUP – 4 ground electrode plug

– Background of making the ground electrode multi-polarized is to ensure durability by distributing the electrode consumption. Multi-electrode plug is effective in improving the discharge characteristics (required voltage reduces).
– BKR6EQUP is a semi-surface discharge type plug. Sparks discharge along the insulator surface and burns away the carbon accumulated on the insulator. This plug has robust anti-carbon fouling performance.

Firing end-projection type plug

(Example) IZFR6K11 (Extended metal shell)

– Stable combustion can be achieved by moving the ignition position to center of the combustion chamber. However, if the projection type plug is used in engines other than those that have been specified, it will hit the piston or valve. Hence, it can only be used for specified vehicles.
– As for extended metal shell type, the ground electrode is designed shorter than the normal plug to reduce load due to heat and vibration.