Douwe EgbertsEgberts CAFITESSE 300 User manual

http://www.globaldenso.com/PLUG/ http://www.denso.co.jp/PLUG/
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Ralf Schumacher
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Casey Stoner

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TOYOTA F1 Team
Taking Malaysian GP
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Taking Malaysian GP
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01

DENSO RACE SUPPORT HISTORYORT HISTORY
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TOYOTAF1TeamTakingMalaysianGP
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GT500Champion
Castrol TOM'S
GT500
CHAMPION
TOYOTA F1 Team
Taking Malaysian GP
Podium Position
TAKING
PODIUM POSITION
TOYOTA F1 Team
Taking Malaysian GP
Podium Position
TAKING
PODIUM POSITION
au Supra
GT500
CHAMPION
Esso Supra
GT500
CHAMPION
Esso Supra
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DENSO SUPPORT DRIVERS & RIDERS
02

DENSO SUPPORT DRIVERS & RIDERS
WRC:SUBARU WORLD RALLY TEAM
Petter Solberg
WGP125 : AJO MOTORSPORTS
Tomoyoshi Koyama
WGP250 : TEAM LCR
Roberto Locatelli
03

CONTENTS
P05
P06
P07
Outline
Chapter 1 1 4-Stroke Engines
2 Role of the ignition System
3 Ignition System Configuration
P08
P08
4 Types of Ignition System
5 Comprehensive Test
P35
P38
P39
Basics of
Ignition
Chapter 3 1 High Voltage Generation
2 High Voltage Control
3 Ignition Timing
P39
P40
4 Ignition Order
5 Comprehensive Test
P09
P13
P15
P25
Spark plugs
Chapter 2
The PLUGS CONFIGURATIONS •••••••••••••••••••••••••••P41
IGNITION TECH Q&A
FAKE PLUG
LINEUP •••••••••••••••••••••••••P61
Q&A
Q&A
1 Spark and ignition
2 Structure
3 Types
4 Heat Range
P27
P29
P31
P34
5 Service Life
6 How to read Sperk Plugs
7 Troubleshooting
8 Comprehensive Test
Q1. What type of spark plug is the ? P43
Q2. Why was the center electrode of the reduced to only 0.4 mm? P44
Q3. How is the iridium tip of the welded to the electrode? P45
Q4. What advantages does the U-groove in the ground electrode have? P46
Q5. What advantages does the tapered cut in the ground electrode have? P47
Q6. What are the differences between and iridium spark plugs
offered as genuine parts by car manufacturers? P48
Q7. What type of material is used to produce the electrode employed for ? P49
Q8. Why can iridium now be used in electrodes? P50
Q9. In what other fields is iridium commonly used for? P50
Q10. Is the tip in the made of pure iridium? P51
Q11. Tell me about the firing performance of the . P52
Q12. Tell me about the required voltage in the . P53
Q13. What happens at idling when an is used? P54
Q14. What happens to fuel consumption when is used? P55
Q15. Does engine performance improve when is used? P56
Q16. Can spark plugs of other brand-names be substituted with ? P57
Q17. What type of cars can current be fitted with ? P58
Q18. Does the engine need to be specially set when fitting ? P58
Q19. How do I select the correct heat-range when fitting to my vehicle? P59
Q20. How would compare against high-performance spark plugs
offered by other spark plug manufacturers? P59
Q21. Is there anything I need to be aware of when fitting ? P60
Q22. Can the gap be adjusted?
Can I use any spark plug cleaners with the ? P60
Q1. What type of spark plug is the ? P66
Q2. What makes the ignitability of so good? P67
Q3. How does the superior ignitability of influence combustion? P68
Q4. How is the iridium tip of the welded to the electrode? P69
Q5. What is the difference between and ? P70
Q6. What patented technologies are used with ? P70
Q7.
What type of material is used to produce the electrode employed for ? P71
Q8. Why can iridium now be used in electrodes? P72
Q9. In what other fields is iridium commonly used for? P72
Q10. Is the tip in the made of pure iridium? P73
Q11. Tell me about the ignitability of the . P74
Q12. Tell me about the required voltage in the . P75
Q13. What happens at emission when an is used? P76
Q14. What happens to fuel consumption when is used? P77
Q15. Does engine performance improve when is used? P78
Q16. How does the compare to the 0.6mm iridium plugs,
platinum plugs and normal spark plugs? P79
Q17. Can spark plugs of other brand-names be substituted with ? P80
Q18. Does the engine need to be specially set when fitting ? P81
Q19. How do I select the correct heat-range when fitting to my vehicle? P81
Q20. How does the compare to iridium plugs from other makers? P82
Q21.
Can be used to replace plugs with 2, 3 or 4 ground electrodes? P83
Q22. Is there anything I need to be aware of when fitting ? P84
Q23. Can the gap be adjusted?
Can I use any spark plug cleaners with the ? P85
Q24. What plugs are in the lineup? P86
SPECIFICATIONS ••••••••••••••••P63
•••••••••••••••••••••••••••••••••P93
••••••••••••••••••••••••••••••••••••••••••P97
SPECIFICATIONS •••••••••••P87
••••••••••••••••••••••••••••••••P88
••••••••••••••••••••••••••••P89
SPECIFICATIONS •••••••••••P91
CROSS REFERENCE ••••••••P92
DENSO Spark Plugs Package Lineup •••••••••••••••••••••P65
04

Spark Plugs
Chapter 1 Outline
Chapter 1 Study Tips
Let us study about the role of the ignition system,
its components parts, and its different types.
Outline
05
4-Stroke Engines
4-Stroke Engines
The 4-stroke engine was first invented by N. Otto in 1876. So it is also known as the
Otto Cycle.
The spark plugs ignite and the gasoline burns driving the piston downwards, creating
power.
Intake Compression Combustion
Intake and compression Combustion and exhaust
Exhaust
Intake Compression Exhaust
These four strokes rotate the crankshaft twice and complete one cycle.
Operation of 4-stroke engines
Intake stroke
1
Takes the air-fuel
mixture into the
cylinder.
Compression stroke
2
Compresses the air-fuel
mixture to high
temperature and high
pressure.
Intake and compression stroke
1
When the piston rises and the cylinder side
compresses, the crank case side is a vacuum and
takes in the air-fuel mixture.
Combustion and exhaust stroke
2
When the piston is pushed down by the combustion,
the air-fuel mixture on the crank case side is sent to
the cylinder side where it pushes out the exhaust gas.
Combustion stroke
3
Ignites and combusts the gas
mixture and uses the resulting
high pressure to rotate the
crankshaft.
Exhaust stroke
4
Exhausts the exhaust
gas.
Combustion
These two strokes complete one cycle during one motion of the piston (one crankshaft rotation).
2-stroke engines do not require moving valves and have a simpler structure, but the compression ratio is low and they are only
appropriate for small displacements.
2-stroke engines
REFERENCE
1

Spark Plugs
Chapter 1 Outline
06
The ignition system applies several thousand volts across the gap between the
electrodes of the spark plug to generate spark to discharge and ignites and combusts
the air-fuel mixture in the cylinder with this spark energy.
Igniting at the optimum time for the varying engine speed, load, etc. is also an
important condition.
Three conditions for attaining the performance of gasoline engines
Good Air-Fuel Mixture
Good Compression
Good Spark
Diesel engines directly inject fuel into high-temperature, high-pressure air and have the fuel ignite on its own, so they do not
require ignition system.
Diesel engine ignition system
REFERENCE
The mixture that makes the gasoline combust most readily
1 Gasified and well mixed with air 2 Always the correct air-fuel ratio (mixture proportions)
By compressing the air-fuel mixture, it is
possible to obtain large power when the
mixture is combusted.
The degree of compression of the air-fuel
mixture is expressed by the following
compression ratio.
Generally, raising the compression ratio
provides larger combustion pressure, but if
the pressure is too high, knocking occurs.
General engines are designed for
compression ratios of 9-10.
The proportion by weight of gasoline and air in the air-fuel mixture; these proportions must be varied with the engine state.
• Stoichiometric air-fuel ratio (about 15:1) Stoichiometric value for complete combustion
• Output air-fuel ratio (about 12:1) The mixture ratio that provides the maximum torque
• Economy air-fuel ratio (about 16:1) The mixture ratio that provides the best fuel economy
• In lean burn engines, this can be as high as about 23:1.
Good Air-Fuel mixture means
Air-Fuel ratio (A/F)
REFERENCE
Compression ratio
REFERENCE
The ignition timing is adjusted to match the running state of the
engine (speed and load) and obtain efficient combustion power.
High voltage of several thousands of volts are applied between
the electrodes of the spark plug for the spark to discharge to
ignite and combust the gas mixture.
"Good spark" is the field for which the ignition system is responsible.
Strong spark Correct ignition timing
REFERENCE
Role of the Ignition System
Role of the Ignition System
1
2
3
2
Compression
ratio
Intake air volume
Compressed air
volume
＝

Spark Plugs
Chapter 1 Outline
Chapter 1 Study Tips
Let us study about the role of the ignition system,
its components parts, and its different types.
Outline
07
Ignition System Configuration
Ignition System Configuration
The ignition system comprises the following parts.
Ignition System Configuration
Battery
1
Supplies current to the primary coil
Ignition coil
2
The high voltage required for ignition is
generated in the secondary coil through coil
self-inductance and mutual inductance.
The high voltage is generated when the
primary current is cut off.
Igniter
3
In order to generate the high
voltage required for ignition in the
ignition coil, the current flowing
through the primary coil is cut off.
Distributor
4
The high voltage generated by the ignition
coil is distributed in the correct order to the
spark plug for each cylinder.
Computer
5
Determines the ignition timing or
the like
Spark plug
6
High voltage is applied to the gap between
the electrodes to generate the spark and
ignite the air-fuel mixture.
3
2
3
4
5
6
1

Spark Plugs
Chapter 1 Outline
08
From the following statements about ignition system, select the incorrect one.
Both gasoline engines and diesel engines require spark plugs to ignite the air-fuel mixture.
The ignition timing is adjusted according to changes in the engine speed and load.
The air-fuel mixture for gasoline engines is the proportion of air and gasoline by weight and about 15:1 is called the stoichiometric air-fuel ratio.
The spark voltage for spark plugs is generated when the primary current through the igniter is cut off.
4-cycle engines ignite and combust each cylinder one time for two rotations for the engine crankshaft.
Answer on next page
Contact Ignition Type
(Ordinary Ignition Type)
Transistor Ignition Type
Electronic Spark Advance (ESA, DLI)
Comprehensive Test
Types of Ignition System
Structurally, ignition system can be classified into the
following three types.
In this system, the current (primary current)
flowing to the ignition coil from the battery is cut
off at the mechanical contacts (breaker points)
in the distributer to generate high voltage.
Demerit
Since these are mechanical contacts,
sparks can fly between the contacts or the
voltage drops at low speed. Also,
sometimes current does not flow adequately
due to soiling of the contact surface.
This system generates high voltage by
cutting off the current with transistors in the
igniter. This system can provide stable high
voltage.
Demerit
The ignition timing is controlled by the signal
generator in the distributor, so there are
limits to fine control.
The ignition timing and dwell angle are
controlled by microcomputer, which sends
the ignition signals to the igniter, where the
transistors inside the igniter cut off the
current and generate high voltage. This
makes more precise control possible and is
the current mainstream ignition system.
Battery
1
Ignition switch
2
Ignition coil
3
Breaker point
4
Distributor
5
Rotor
6
Spark plug
7
Battery
1
Ignition switch
2
Coil with an igniter
3
Signal generator
4
Distributor
5
Rotor
Spark plug
Distributor ECU Igniter
Ignition
Ignition
Engine speed .NE
Ignition
signal
IGt
IGf
Crankshaft
position detection .G
Sensors
Air flow sensor
Water temperature
sensor Air conditioner
signal etc
1
2
3
4
5
6
7
Ignition timing
control
Dwell angle
control
Constant-current
control
Dwell angle
reduction
Types of Ignition System
Electronic ignition type
(ESA:Electronic Spark Advance,
DLI:Distributorless Ignition)
Ignition monitor signal
Comprehensive Test
4
5

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
09
1Spark and Ignition
Spark and Ignition
Spark
When the high voltage produced by the
ignition system is applied between the
center electrode and ground electrode of
the spark plug, the insulation between the
electrodes breaks down, current flows in
the discharge phenomenon, and an
electrical spark is generated.
This spark energy trigger ignition and
combustion in the compressed air-fuel
mixture.
This discharge is of extremely brief
duration (about 1/1000 of a second)
and is extraordinarily complex.
The role of the spark plug is to reliably
generate a strong spark between the
electrodes accurately at the specified
time to create the trigger for combustion
of the gas mixture.
Ignition
Ignition by electrical spark occurs because the fuel particles between the electrodes are activated by the spark to discharge, a
chemical reaction (oxidation) is triggered, the heat of reaction is generated, and the flame core is formed. This heat activates the
surrounding air-fuel mixture, eventually a flame core is formed that spreads the combustion to the surroundings itself.
However, if the quenching effect between the electrodes (the work of the electrodes absorbing the heat and extinguishing the flame) is
greater than the flame core heat generation action, the flame core is extingushed and the combustion stops.
If the plug gap is wide, the flame core is larger and the quenching effect is smaller, so reliable ignition can be expected, but if the gap
is too wide, a large discharge voltage becomes necessary, the limits of the coil performance are exceeded, and discharge becomes
impossible.
Formation of the flame core Quenching effect
High melting point
Sparking wear
Center electrode Ground electrode Flame core Heat absorption Flame propagation
5
5
4
4
3
3
2
2
1
1
10,000 deg.C
1
1
2
2
3
3
4
4
4
4
5
5
Answer: 1

Spark Plugs
Chapter 2 Spark Plugs
10
1
1
2
2
3
3
4
4
5
5
1
2
3
4
−10kV〜30kV
Va
b
c
de
T
−300V
Change in the required voltage
The ignition system normally generates 10-30 kV secondary voltage.
1. When the primary
current is cut off at the 'a'
point, the secondary
voltage rises.
2. At the 'b' point,
partway through the rise
in voltage, the spark plug
reaches the required
voltage and a spark is
generated between the
electrodes.
3. Between 'b' and 'c' is
called the capacitance
spark. At the start of the
discharge, the spark is
generated by the
electrical energy stored in
the secondary circuit.
The current is large but
the duration is short.
4. Between 'c' and 'd' is
called the inductance
spark. The spark is
generated by the
electromagnetic energy
of the coil. The current is
small but the duration is
long. From the 'c' point,
the discharge is
continued for about 1
millisecond and at the 'd'
point, the discharge
ends.
Voltage rise Spark generation Capacitance spark Inductance spark
About 1 millisecond V: Voltage T: Time
5
5
4
4
3
3
2
2
1
1

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
11
The required voltage changes drastically
with various conditions.
The three factors with
particularly large impact are
the spark plug gap, the
compression pressure, and the
air-fuel mixture temperature.
The required voltage rises in proportion
to the spark plug gap.
The spark plug gap widens bit by bit as
the electrode wears, so high required
voltage becomes necessary and misfire
occurs more easily.
Spark Plug Gap
1
●Conditions that affect
the required voltage
G: Spark plug gap V: Required voltage
Even for the same spark plug gap, if
there are edges on the electrode,
discharge occurs more easily.
Older spark plugs have electrodes that
have rounded, so discharge becomes
more difficult and misfire more likely.
Electrode shape
2
Easy discharge Difficult spark
Electrode shape
3
3
2
2
1
1
The required voltage rises in proportion to the
compression pressure.
The compression pressure is higher for low speed
and high load. Sudden acceleration for starting
out fits these conditions, so higher voltage is
required then and misfire occurs more easily.
Compression pressure
3
P: Compression pressure T: Air-Fuel mixture
temperature V: Required voltage
The required voltage drops as the air-
fuel mixture temperature rises.
The lower the engine temperature, the
higher the required voltage, so misfire
occurs more easily at low temperature.
Air-Fuel mixture temperature
4
P: Compression pressure T: Air-Fuel mixture
temperature V: Required voltage
As the humidity rises, the electrode
temperature decreases, so the required
voltage becomes slightly higher.
Humidity
7
H: Relative humidity V: Required voltage
The required voltage drops as the
electrode temperature rises.
The electrode temperature rises in
proportion to the engine speed, so
misfire occurs more easily at low speed.
Electrode temperature
5
T: Electrode temperature V: Required voltage
There is a tendency for the required
voltage to be higher the leaner the air-
fuel mixture (the larger the air-fuel ratio).
If the air-fuel mixture becomes leaner
due to fuel system trouble misfire occurs
more easily.
Air-Fuel ratio
6
A/F: Air-fuel ratio V: Required voltage

Spark Plugs
Chapter 2 Spark Plugs
12
The effect on the spark plugs of ignition and combustion of the running
engine is severe and various aspects of performance for withstanding this
are required.
The temperature received by the inside
surface of the spark plug reaches as high
as 3000°C during combustion of the air-fuel
mixture and during the intake stroke, the
spark plug is subject to sudden cooling by
low-temperature gas. In 4-cycle engines,
this sudden heating and sudden cooling is
repeated every other rotation as long as the
engine is running.
As the same time that it must provide such
capacity to withstand heat, the spark plug
must also give off enough heat to avoid
becoming a starting point for pre ignition.
Can withstand sudden heat
and sudden cold
1
In the intake stroke, the pressure is less
than 1atm, but in the combustion stroke
it reaches 50 atm or higher. The
mechanical strength to withstand this
severe pressure change is required.
Can withstand severe
pressure changes.
2
In an environment in which the temperature
and pressure are constantly changing
drastically, spark plugs must have
adequate insulation to withstand high
voltages that reach about 10-30 kV.
Has insulation at high voltage
3
Spark plugs must maintain an airtight
seal between the housing and the
insulator under conditions of drastic
temperature and pressure change and
high voltage.
DENSO's heat staking process provides
stable air tightness.
Maintains an airtight seal in
a harsh environment
4
Spark plugs must have the wear-proof
resistance to minimize electrode wear in a
severe usage environment.
DENSO's patented iridium alloy is effective
against wear.
Minimizes electrode wear
5
It is required that under severe usage
conditions, spark plugs minimize fouling
of electrodes by the combustion of the air-
fuel mixture and have self-cleaning that
burns away carbon deposits with heat.
Therefore, it is desirable that the spark
plug temperature rise quickly even when
the vehicle is moving at low speed and
that the insulator section reach the self-
cleaning temperature (about 500°C ).
Minimizes fouling from
combustion
6
●Performance required of spark plugs
｛
3
4
1 2 5
6

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
13
2Structure
Structure
A spark plug consists of three main parts, the housing, the
insulator, and the electrodes.
Let us take a look at the figure, which shows an spark plug as an example,
and look at the features of each part.
Insulator
Terminal
Ring
Center shaft (stem)
Housing
Glass seal
Gasket
Electrode with copper
Packing washer
0.4-mm iridium center electrode
U-groove ground electrode
Taper cut ground electrode
12
12
11
11
10
10
9
9
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
Insulates the terminal, center shaft and
center electrode from the housing,
preventing escape of high voltage from the
electrodes.
Since the bottom of the insulator projects
into the combustion chamber, high purity
alumina with superior heat-proof
characteristic, mechanical strength,
excellent insulation and thermal conductivity
at high temperature, etc. is used.
Insulator
1
1
The terminal is connected to a high-tension
cord through which high-voltage current
from the ignition system flows.
A terminal nut is installed so this type can
support almost any high-tension cord in the
world. For vehicles not requiring a terminal
nut, the terminal can be removed.
Terminal
2
2
Makes the insulator and the housing fit
tightly to each other and maintains the
airtightness.
Ring, Packing washer
3
3
9
9
4
4
2
2
6
6
8
8
1
1
3
3
5
5
9
9
7
7
11
11
12
12
10
10

Spark Plugs
Chapter 2 Spark Plugs
14
Standard tightening torque
Center shaft connecting the terminal and
the center electrode.
This shaft is made of steel and has the role
of allowing high-voltage current to flow from
the terminal to the center electrode without
loss.
Center shaft (stem)
4
4
The housing forms an outer shell that
surrounds the insulator, supports the
insulator, and installs the spark plug in the
engine.
At the bottom the ground electrode is
located, so current can flow through the
engine itself to the center electrode over the
gap.
Housing
5
5
Mounted between the center shaft and
insulator to maintain the airtightness.
DENSO uses the glass seal method.
A special mixture of glass powder and
copper powder is charged in the installation
section for the insulator and center shaft
and center electrode and melted at high
temperature. This bonds the center shaft
and the center electrode and fuses the
insulator and the metal.
The sealing for both is good and the thermal
ratio of expansion is appropriate, so even
under harsh conditions gaps do not occur
and good airtightness can be secured.
Glass seal
6
6
Makes the housing and the engine fit tightly
to each other and maintains the airtightness
of the combustion chamber.
There is a procedure for tightening and the
appropriate tightening margin must be
secured.
Gasket
7
7
Special nickel alloy is used for the center
electrode to reduce electrode wear.
Copper is sealed into the center section to
improve thermal conductivity.
Electrode with copper
8
8
A new iridium alloy tip with a diameter of 0.4
mm is laser welded to the tip of the center
electrode to make the center electrode
ultra-fine.
This lowers the required voltage, secure
reliable spark, reduces the quenching
effect, and improves ignition performance.
Iridium, like platinum, is a precious metal
and has extraordinarily superior properties
for a spark plug electrode, for example high-
temperature withstand, high strength, and
low resistance. In order to further improve
oxidation resistance at high temperatures,
DENSO developed a unique new iridium
alloy containing Rhodium.
0.4-mm iridium center
electrode
10
10
The ground electrode has a shape in which
the electrode tip is cut to a finely tapered
shape.
This reduces the quenching effect, so it
improves ignition performance.
Taper cut ground electrode
12
12
Thread diameter
(mm)
Tightening torque
(Nm)
8
10
12
14
18
8 〜10
10〜15
15〜20
20〜30
30〜40
Nickel chrome material is used for the
ground electrode and various measures are
taken with the shape to improve ignition
performance.
One of these measures is the U- groove.
1 The surface contacted by the air-fuel
mixture is large,
2 There is much edge section, and sparks
occur easily.
3 The flame core (flame size) widens easily.
There are many other feaures as well and
large ignition energy can be obtained.
DENSO obtained patents for spark plug U-
grooves from 1975 to 1992.
U-groove ground electrode
11
11

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
15
3Types
Types
1 2 3
Needle to needle
Iridium Plug
4
Genuine iridium
5Resistor 6U-groove 7Platinum ZU 8
Platinum
9For rotary use 10
Extended
11
Semi-surface
discharge
12
3 electrodes
13
Compact type
14
Taper seat
15
For motorcycle
16
Main types of spark plugs
P.16 P.17 P.18 P.18
P.19 P.19 P.20 P.20
P.21 P.21 P.22 P.22
P.23 P.23 P.23 P.24

Spark Plugs
Chapter 2 Spark Plugs
16
(2)
1
●Uses the world's first and the world's
smallest ultra-fine 0.4-mm diameter
iridium tip for the center electrode. This
lowers the required voltage and greatly
improves ignitability.
●The inside of the ground electrode
has a U-shaped groove to secure the
large space required for flame core
formation. This provides superior
ignition performance with low spark
voltage without enlarging the plug gap.
●The ground electrode tip is cut to a
shape with a tapered tip. This reduces
the quenching effect and greatly
improves ignitability.
Taper cut ground electrode
U-groove ground electrode
Ultra-fine 0.4-mm diameter iridium
alloy center electrode
Increased center electrode projection Insulator projection All-round laser welding
Terminal Nut
Built-in high-reliability resistor Plated with highly corrosion resistant nickel
9
9
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
●The finer the electrodes, the more
the potential concent-rates at the
electrode tip and the stronger the
electrical field, so the lower the
required voltage. Therefore, reliable
combusion is obtained over a wide
range and engine starting and
acceleration are improved.
Normal spark plugs
Weak
Electrical field strength
Strong
5
5
4
4
3
3
2
2
1
1
Electrical field strength shown using FEM analysis
1(1)
1(2)
(1)
1
9
9
8
8
7
7
1
1
3
3
2
2
5
5
1
12
2
3
3
4
4
5
5
6
6
4
4

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
17
●The center electrode uses the
world's first ultra-fine 0.4-mm diameter
iridium alloy for high performance and
a platinum tip is used for the ground
electrode to secure service life equal
to platinum spark plugs.
Ground electrode with platinum tip
Ultra-fine 0.4-mm diameter iridium
alloy center electrode
All-round laser welding
Housing plated with highly
corrosion-resistant, lustrous nickel
4
4
3
3
2
2
1
1
●The electrodes have been taken to the limit of fineness, so the contact area with the flame core is small, the quenching effect is
reduced, and the ignition performance is improved.
●can replace almost all normal spark plugs in Japan and overseas. When replacing normal spark plugs with
check in the application table.
●For normal engines, replace with the same heat range as the spark plugs being replaced; for a tuned engine, select spark plugs that
match the tuning level.
Sparks
Sparks discharge on the part
of the electrode where they
can spark most easily.
Formation of the flame core
The spark energy activates
part of the air-fuel mixture and
a small flame is produced.
Growth of the flame core
The flame grows even though
energy is absorbed in the
center and ground electrodes.
Ignition
Growth of the live coal
accelerates and finally, the
flame spreads as explosive
combustion.
4
4
3
3
2
2
1
1
1
1
2
2
3
3
4
4
1(3)
2
(3)
1
2
4
4
1
1
3
3
2
2

Spark Plugs
Chapter 2 Spark Plugs
18
●Combining the ultra-fine 0.4-mm
diameter iridium alloy center electrode
with the 0.8-mm square all-platinum
ground electrode, spark cleaning
pocket, housing end chamfer, silicon
oil application, racing insulator, etc.
greatly improves ignition performance
and extends durability.
0.8 mm square all-platinum ground
electrode
Ultra-fine 0.4-mm diameter iridium
alloy center electrode
Racing insulator
Spark cleaning pocket
Silicon oil application
Housing end chamfer
All-round laser welding
Terminal
Built-in high-reliability resistor
Plated with highly corrosion resistant
nickel
10
10
9
9
8
8
7
7
6
6
5
5
4
4
3
3
2
2
1
1
●The ground electrode of this
revolutionary iridium plug features
DENSO's very own technology and is
needle-shaped, resulting in an
unparalleled reduction in quenching
action.
0.55mm diameter. Iridium
0.7mm diameter. Platinum
2
2
1
1
Needle to needle
Iridium Plug
44
3
3
10
10
9
9
8
8
1
1
4
4
3
3
2
2
5
5
6
6
7
7
1
1
2
2
FXE20HE11

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.
Iridiumφ0.7 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
13
3
2
2
2
2