Mazda 2006 MX-5 - Determination of Ignition Timing

CONTROL SYSTEM
01–40–27
01–40
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.
Ignition timing calculation method table
A: Ignition timing base, B: Correction for ignition timing
THROTTLE
VALVE
POSITION
ENGINE SPEED
START
ZONE
REGULAR ZONE
IDLE ZONE
OPEN
CLOSED
LOW
HIGH
C3U0140S020
Control zone Control condition Ignition method
Start zone
Engine speed is 500 rpm or less.
When MAF sensor is damaged.
Fixed ignition
Idle zone
Fully-closed throttle valve when engine speed is the
target idle speed + 1,750 rpm or less
Determines ignition timing adding each correction
to the idle spark advance
Cycle estimated
zone
Engine operation except start zone and idle zone
Determines ignition timing adding each correction
to the basic spark advance
Contents
Calculation method or determination method for ignition timing,
advance value and correction
Control zone
Fixed ignition Fixed at BTDC approx. 8 ° CA A
Cycle
estimated
ignition
Idle spark
advance
Set value according to target speed and charging efficiency
*
A
Basic spark
advance
Set value according to engine speed and charging efficiency
*
A
Start zone Idling zone
Cycle estimated zone