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ELECTRONIC SPARK ADVANCE CONTROL [SKYACTIV-G 2.0]

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2016 – MX-5 – Engine

ELECTRONIC SPARK ADVANCE CONTROL [SKYACTIV-G 2.0]

Outline

Controls ignition for 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. This causes the spark plugs to discharge (ignite) by the effect of electromagnetic mutual induction.

Block Diagram

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

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
Start zone	Engine speed is less than 500 rpm	Engine starting
Normal zone	Engine operation except start zone	Cycle estimated ignition (Determines ignition timing adding each correction to basic spark advance)

Ignition timing calculation method tableA: Ignition timing base, B: Correction for ignition timing

Contents		Calculation method or determination method for ignition timing, spark advance, and correction	Control zone
Contents			Start zone	Normal zone
Starting ignition		Determination based on engine coolant temperature	A
Cycle estimated ignition	Basic spark advance	Set value according to engine speed and charging efficiency^*		A
Correction	Engine coolant temperature spark advance correction	Purpose: Ensures combustion stability when engine coolant temperature is low According to engine coolant temperature High charging efficiency^*, low engine coolant temperature???large correction		B
	Intake air temperature correction	Purpose: Suppresses knocking when engine intake air temperature is high According to engine intake air temperature and engine coolant temperature High engine intake air temperature, high engine coolant temperature???large correction		B
	Warm-up promotion spark retard correction	Purpose: Activates the catalytic converter earlier Maximum 50 s after engine start According to engine coolant temperature???correction		B
	Torque reduction correction	Purpose: Such as reduction of shift shock, traction control, or suppression of vehicle vibration According to torque reduction request from TCM, or DSC HU/CM Large torque reduction request???large correction		B
	Knocking spark retard correction	Purpose: Knocking suppression *Acceleration when charging efficiency volume increase (acceleration amount) is given value or more** Large acceleration amount???large correction		B
	Valve timing correction	Purpose: Ensures combustion stability When phase difference changes due to electric variable valve timing control and hydraulic variable valve timing control Correction according to change in phase difference		B

^*: 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.

If immobilizer system related information (engine start prohibited) is received from the start stop unit, the PCM stops ignition.
When a collision signal is received from the SAS control module, the PCM stops the ignition.

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