Spark Plugs
Chapter 2
Study Tips
The spark plugs are critical parts that dominate
the engine combustion and bear a major
responsibility for higher engine performance.
Spark Plugs
Chapter 2 Spark Plugs
21
Platinum spark plugs
9
Platinum tip
1
1
For rotary engines only
10
●
These special spark plugs for rotary engines were
designed taking into account the characteristics rotary
engines give spark plugs.
●
With rotary engines, heat remains in the ground
electrodes and they melt, so to match the higher engine
temperature, improvements have been made EA
→
EDR
→
semi-surface discharge
→
surface discharge.
EA spark plug (initial rotary engine spark plug)
This spark has two short facing ground electrodes.
EDR spark plug (transitional period)
This spark plug has four ground electrodes.
It has a built-in resistor to prevent the generation
of electromagnetic interference.
Surface-discharge spark plugs
The surface-discharge action improves ignition,
fouling-proof, and durability.
3
3
2
2
1
1
10
Example : PK20R11
●
These spark plugs have platinum tips welded to the
center electrode and ground electrode.
●
The tips of the center electrodes are finer than those
of ordinary spark plugs.
●
They greatly improve fuel consumption, driveability,
and durability and support maintenance-free operation.
~ For DLI (+ - discharge)
Platinum spark plugs
Example : PK20R-P11
●
In order to prevent wear from + discharge, the volume
of platinum for the ground electrodes has been
increased.
- Extended platinum spark plugs
Example : PKJ20CR-L11
●
Extended the spark position into the combustion
chamber improves the combustion efficiency, fuel
consumption, and driveability.
- 2-electrode platinum spark plugs
Example: PK20TR11
●
Platinum tips are bonded to the center electrode
facing to the ground electrode section.
●
The 2-electrode structure reduces the voltage
required for + discharge.
- Single platinum spark plugs
Example : Q20PR-P11
K16PR-TP11
●
These spark plugs use platinum only for the tip of the
center electrode to improve fuel consumption,
driveability, and durability by making the electrodes finer.
●
The K16PR-TP11 has a tapered cut ground electrode
to further improve ignition performance.
1
1
2
2
3
3
PK20TR11
PK20R11
PK20R-P11
PKJ20CR-L11
PK20TR11
Q20PR-P11, K16PR-TP11
1
1
9
W25EA
W27EDR14
S29A
