ELECTRONIC SPARK ADVANCE CONTROL [SKYACTIV-X 2.0]

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Outline

• Controls ignition to optimum timing according to engine operation conditions.

• Serviceability has been improved by eliminating the necessity of ignition timing adjustment.

• The PCM determines the engine operation conditions based on input signals from each sensor and blocks current to the ignition coils at the calculated ignition timing, causing the spark plugs to discharge (ignite) by the effect of electromagnetic mutual induction.

Block Diagram

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Operation

Ignition method

• The PCM energizes the ignition coils according to the ignition timing calculated from the engine operation conditions and the igniter energization time.

• The igniter energization time (ignition coil energization time) is determined according to battery voltage and engine speed.

Timing chart

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Determination of Ignition Timing

Division of control zones

• The PCM performs different ignition controls for engine starting and those other than engine starting to stabilize the engine starting.

Control zone

Control condition

Ignition method

Engine start zone

Engine speed is less than 500 rpm

Engine starting

IR zone

During IR

IR ignition

Normal zone

During engine operation except for engine start zone and IR zone

Normal ignition (ignition timing is determined based on information from cylinder pressure sensor)

Control zone	Control condition	Ignition method
Engine start zone	Engine speed is less than 500 rpm	Engine starting
IR zone	During IR	IR ignition
Normal zone	During engine operation except for engine start zone and IR zone	Normal ignition (ignition timing is determined based on information from cylinder pressure sensor)

Ignition timing calculation method table

A: Ignition timing base, B: Correction for ignition timing

Contents		Calculation method or determination method for ignition timing, spark advance, and correction	Control zone
Contents
Starting ignition		Determination based on engine coolant temperature	A
IR ignition		Determination based on engine coolant temperature	A
Normal ignition		Determination based on conditions inside cylinder (operation conditions of pressure, temperature, EGR, and each device and cylinder pressure sensor condition)		A
Correction	Engine coolant temperature spark advance correction	Purpose: Correction is performed because knocking and combustion period differ according to engine coolant temperature (temperature of wall inside cylinder).		B
	Intake air temperature correction	Purpose: Correction is performed because SPCCI (Spark Controlled Compression Ignition) occurrence differs according to intake air temperature.		B
	G/F correction (inside and outside)	Purpose: Correction is performed because knocking and combustion period differ according to EGR rate or fuel-air equivalence ratio.		B
	Valve timing correction	Purpose: Correction is performed because combustion speed changes according to electric variable valve timing.		B
	Swirl control valve position correction	Purpose: Correction is performed because combustion speed changes according to swirl control valve opening angle.		B

• If immobilizer system related information (engine start prohibited) is received from the BCM, the PCM stops ignition.

• When a collision signal is received from the SAS control module, the PCM stops the ignition.