compression ratio MITSUBISHI LANCER 2006 Workshop Manual

IGNITION SYSTEM
ENGINE ELECTRICAL16-30
IGNITION SYSTEM
GENERAL INFORMATIONM1163000100294
This system is equipped with two ignition coils (A and
B) with built-in power transistors for the No. 1 and
No. 4 cylinders and the No. 2 and No. 3 cylinders
respectively.
Interruption of the primary current flowing in the pri-
mary side of ignition coil A generates a high voltage
in the secondary side of ignition coil A. The high volt
-
age thus generated is applied to the spark plugs of
No. 1 and No. 4 cylinders to generate sparks. At the
time that the sparks are generated at both spark
plugs, if one cylinder is at the compression stroke,
the other cylinder is at the exhaust stroke, so that
ignition of the compressed air/fuel mixture occurs
only for the cylinder which is at the compression
stroke.
In the same way, when the primary current flowing in
ignition coil B is interrupted, the high voltage thus
generated is applied to the spark plugs of No. 2 and
No. 3 cylinders.
The engine-ECU or engine-A/T-ECU
turns the two power transistors inside the ignition
coils alternately on and off. This causes the primary
currents in the ignition coils to be alternately inter
-
rupted and allowed to flow to fire the cylinders in the
order 1-3-4-2.
The engine-ECU or engine-A/T-ECU
determines which ignition coil should be controlled
by means of the signals from the camshaft position
sensor which is incorporated in the camshaft and
from the crank angle sensor which is incorporated in
the crankshaft. It also detects the crankshaft position
in order to provide ignition at the most appropriate
timing in response to the engine operation condi
-
tions. It also detects the crankshaft position in order
to provide ignition at the most appropriate timing in
response to the engine operation conditions.
When the engine is cold or operated at high alti-
tudes, the ignition timing is slightly advanced to pro-
vide optimum performance.
When the automatic transmission shifts gears, the
ignition timing is also retarded in order to reduce out
-
put torque, thereby alleviating shifting shocks.
SYSTEM DIAGRAM
AK101074
Air flow sensor
<4G6> MAP sensor <4G1>
Intake air temperatur
sensor
Engine coolant
temperature sensor
Camshaft position
sensor
Crank angle sensor
Barometric pressure
sonsor <4G6>
Detonatoin sensor
Ignition switch-ST Engine-A/T-
ECU Engine-ECU

Ignition coil B
Cylinder No. 23 4
AG
1
Spark plug Ignition coil A
Ignition
switch
Battery

IGNITION SYSTEM
ENGINE ELECTRICAL16-35
Observation Conditions (The only change from above condition is the pattern selector.)
Pattern selectorDisplay
AKX01275
kV
Secondary ignition
voltage wave pattern 0
2NO. 1 cylinder
NO. 3 cylinder
ignition noise
Newtral section NO. 4 cylinder
NO. 2 cylinder
ignition noise
Time
AC
WA VEFORM OBSER V A T ION POINTS
Point A: The he ight, len g th and s l ope of th e sp a r k line sho w the following trends (Re f er to abnorma l
wave
form exam ples, 1 , 2, 3 a nd 4).
Spark linePlug gapCondition of
electrodeCompression
force Concentration
of air mixtureIgnition
timingSpark plug
cable
LengthLongSmallNormalLowRichAdvancedLeak
ShortLargeLarge wearHigh LeanRetardedHigh
resistance
HeightHighLargeLarge wearHighLeanRetardedHigh
resistance
LowSmallNormalLow RichAdvancedLeak
SlopeLargePlug is fouled−−−−
Point B: Number of v i bra t ion in red uction vi bra t ion sec tion (Refer to a bnormal wavefo r m examp l e 5)
Number of vibrationsCoil and condenser
3 or moreNormal
Except aboveAbnormal
Point C: Number of v i bra t ions a t beginnin g of dwell se ction (Refer to a bnormal wave form exam ple 5)
Number of vibrationsCoil
5 − 6 or higherNormal
Except aboveAbnormal
Point D: Ignition volt a g e height (distribution per each cylinder) s hows the follo wing tren ds.
Ignition
voltagePlug gapCondition of
electrodeCompression
forceConcentration
of air mixtureIgnition
timingSpark plug
cable
HighLargeLarge wearHighLeanRetardedHigh
resistance
LowSmallNormalLowRichAdvancedLeak