ELECTRONIC SPARK ADVANCE (ESA) OPERATION [L3 R.H.D.]

BUE014000000N27

Ignition method

• The PCM excites the ignition coils employing either fixed ignition or cycle estimated ignition according to engine operation conditions.


Ignition method	Ignition timing	Ignition coil energization period
Fixed ignition	Fixed at BTDC 10°	Fixed period at BTDC 10° to end of energization
Cycle estimated ignition	Ignition at timing appropriate to engine operation conditions based on input signals	• Energization time to igniter (ignition coil energization time) is determined according to battery voltage • Ignition by paired ignition system (cylinders 1, 4 simultaneously; cylinders 2, 3 simultaneously)

Timing chart


1	CMP sensor input
2	CKP sensor input
3	Cylinder number
4	Intake air
5	Exhaust air
6	Expansion
7	Compression
8	Ignition coil energization allowance period
9	Fuel ignition

Determination of Ignition Timing

Division of control zones

• The PCM divides the engine control operations into each control zone according to the engine speed and throttle valve opening angle to determine the ignition timing by each of the control zones to perform optimum ignition control under all engine operation conditions.


1	Throttle valve position
2	Engine speed
3	Start zone
4	Regular zone
5	Idle zone
6	Cycle estimated ignition
7	Fixed ignition
8	Open
9	Closed
10	Low
11	High


Control zone	Control condition	Ignition method
Start zone	Engine speed 500 rpm or less MAF sensor malfunction	Fixed ignition
Idle zone	Fully-closed throttle valve when engine speed is at the target idle speed + 1,750 rpm or less	Determines ignition timing adding each correction to the idle spark advance
Regular zone	Engine operation except start and idling zones	Determines ignition timing adding each correction to the basic spark advance

Ignition timing calculation method table

*: Ignition timing base, x: Correction for ignition timing


Contents		Calculation method or determination method for ignition timing, spark advance, and correction	Control zone
Contents
Fixed ignition		Fixed at BTDC approx. 10° CA	*
Cycle estimated ignition	Idle spark advance	Set value according to target speed and charging efficiency^*		*
Cycle estimated ignition	Basic spark advance	Set value according to engine speed and charging efficiency^*			*
Correction	Engine coolant temperature advance correction	Purpose: Ensures combustion stability when engine coolant temperature is low Except idling • High charging efficiency^*, low engine coolant temperature→large correction		x	x
	Warm-up promotion spark retard correction	Purpose: Activates the catalytic converter earlier Approx. 20 s after engine start • Low engine coolant temperature→large correction		x
	Feedback correction	Purpose: Ensures idling stability While idling (inhibited during test mode) • Large difference between actual engine speed and target engine speed→large correction • Small difference between actual engine speed and target engine speed→small correction		x
	EGR correction	Purpose: Prevents deviation of required ignition timing during EGR gas feed When EGR valve position is the specified value or more except during EGR valve initialization • According to engine speed and charging efficiency^*→correction			x
	Shift retard correction	Purpose: Reduces shift shock during downshifting Determined according to torque reduction request signal from the ATX control • Large torque reduction request during shifting→large correction			x
	Deceleration fuel cut recovery retard correction	Purpose: Reduces shock after recovery from deceleration fuel cut and during re-acceleration while in deceleration fuel cut After recovery from deceleration fuel cut and re-acceleration during in deceleration fuel cut • Low engine coolant temperature→large correction		x	x
	Acceleration spark retard correction	Purpose: Prevents knocking and shock during sudden acceleration *Acceleration when charging efficiency^ volume increase (acceleration amount) is given value or more** • High acceleration amount→high retard			x
	Acceleration from standstill spark retard correction	Purpose: Prevents shock when vehicle accelerates from a standstill According to intake air temperature at acceleration from standstill • Low intake air temperature→high retard			x
	Knocking spark retard correction	Purpose: Knocking suppression When knocking is detected while driving with load • Large amount of knocking→large correction			x

^* :

Charging efficiency is the ratio of the actual amount of intake air to the maximum air charging amount (mass volume) of the cylinder. This value increases proportionately to the increase in engine load.