Toyota COMPUTER-CONTROLLED SYSTEM Training Manual page 101

ESA - Functions of Engine EC U
FUNCTIONS OF ENGINE ECU
1 . IGNITION TIMING CONTRO L
Ignition timing control consists of two basic controls :
• Sta
rt
ing ignition contro l
When the engine is cranking, ignition occurs at a
certain fixed crankshaft angle, regardless of
engine operating conditions . This is called
"initial ignition timing angle" .
Initial ignition timing angl e
OHP 65
Initial ignition timing angl e
!4 01
Actual ignition timing
OHP 6 5
REFERENCE
Note that, in after-start ignition control, each
type of correction differs depending on the
engine model .
Ignition
timing
control
Sta
rt
ing ignition control
Initial ignition timing angl e
Initial ignition timing angle
Basic ignition advance angl e
After-sta
rt
ignition control
• After-start ignition contro l
Various corrections are added to the initial
ignition timing angle and the basic ignition
advance angle during normal operation .
Corrective
ignition
advance
control
Warm-up correction
Over-temp . correction
Stable idling correction
EGR correctio n
Air-fuel ratio feedback correction
Knocking correctio n
Torque control correction
Other correction
Maximum and minimum
advance angle control
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