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
19
Vehicle
manufacturer's
genuine iridium
spark plugs
5
●
Compared to ,
, and
, which emphasize
performance, this type emphasizes
maintenance (service life).
●
The replacement interval is 100,000 km.
●
The center electrode is 0.7-mm
iridium alloy and a platinum tip is used
for the ground electrode.
- Iridium plug
Example : SK16R-P11
SK20R11
●
Denso developed the world's first
ultra-fine 0.7-mm diameter iridium alloy
spark plugs to greatly improve ignition
performance and service life.
The SK16R-P11 is used as the
genuine spark plugs for the Toyota
Century.
- New 3-electrode iridium spark
plugs
Example: SK20BR11
●
The design of these spark plugs is
optimized for direct injection burning off
carbon. The spark is at the main electrode
normally and at the side electrode when
the main electrode is sooty.
Used as the genuine spark plugs for
the Toyota Crown 3-liter direct injection
engine.
Iridium
φ
0.7 tip
Platinum tip
Side electrode
3
3
2
2
1
1
Resistor
1
1
Resistor plug
6
●
In order to prevent the generation of
electromagnetic noise, the spark plug
has resistor (5 kilo-ohms) built into the
glass seal section.
●
This resistance suppresses the
capacitance dischage power during
discharge and can greatly reduce the
electromagnetic noise.
●
Recently, with the increased use of
electronic products in vehicles, the
majority of spark plugs installed in new
vehicles have resistors.
K16R-U11
6
5
1
1
SK20R11
SK16R-P11, SK20R11
SK20BR11
1
1
1
1
3
3
2
2
2
2
