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
23
3 electrodes
13
●
There are three ground electrodes for increased
durability.
●
For Audi, VW, Citroen, Fiat, Mercedes-Benz, and
Renault.
Compact type
14
Taper seat
15
●
A special type of spark plug for foreign vehicles only;
this type has no gasket.
14
13
15
K22PB, W20EPB
Q16R-U11
K16R-U11
XU22EPR-U
QL20PR-U/QL20TR-S
●
Compact and light weight (contributes to improved
fuel consumption).
- Compact spark plugs
Example : Q16R-U11
Q16PR-U11
●
By reducing the hexagonal width across flats (to 16
mm), lighter spark plugs were attained.
- ISO compact spark plugs
Example : K16R-U11
K16PR-U11
●
Spark plugs that meet ISO standards.
* Be careful when installing these spark plugs. The
height (H) is 2.5 mm shorter than for the Q type.
- Compact spark plugs for mini-sized cars
Example : XU22EPR-U
●
By reducing the hexagonal width across flats (to 16
mm), these spark were made usable in mini-sized cars.
The thread diameter is 12 mm.
- Compact, long-torso spark plugs
Example : QL20PR-U
QL20TR-S
●
The housing torso section is lengthened to secure the
installation dimensions.
●
Only for Daihatsu.
●
The QL20TR-S has two ground electrodes and a
semi-surface discharge, so it has improved fouling-
proofing.
T16EPR-U
53mm
50.5mm
