IDLE Tab
Idle RPM Control
Idle RPM is controlled by varying the AAC valve PWM idle duty based
on the idle RPM error, or difference between target idle RPM and actual RPM. The idle duty is initialized
from the Initial Idle Duty table based on ECT. Target idle RPM is set from the Base Target Idle RPM
table, also based on ECT.
- Total Min Duty - This is the minimum idle duty allowed.
- Total Max Duty - This is the maximum idle duty allowed.
- A/C ON MIN RPM - This sets the minimum target idle RPM with A/C on.
- Low Batt. Volt Min RPM - If the battery voltage drops below 12V for more than 1.28 seconds, target idle RPM is not allowed to drop below this RPM for 5 minutes.
- Base Target Idle RPM - Use this table to set the desired target idle RPM based on ECT.
- Initial Idle Duty - While the engine is cranking, idle duty is set from this table based on ECT. This is the initial value of idle duty and is not used to control idle RPM.
- Post Start Fast Idle - The first 7 seconds after the engine starts, target idle RPM is increased by the percentage from this table.
IDLE RECOVERY
Idle Recovery Mode
Idle recovery mode is entered when the throttle closes. The Idle Recovery Duty is set based on the RPM when
the throttle closes and is decremented at the rate set by the Decay Timer.
The idle control system stays in this mode while a) the throttle is closed, b) the tranmission is in gear,
c) the clutch is engaged (if clutch switch enabled), and d) the vehicle speed is above
Min Speed (Overrun Mode).
If the throttle is still closed when any of the listed "Idle Recovery Mode" conditions are not met,
this mode is exited. When either the Idle Recovery Timer has expired, or RPM drops to target idle RPM,
"Idle RPM Control Mode" is entered.
Idle Recovery Parameters
- Decay Timer - This controls the rate at which Idle Recovery Duty is decreased.
- Min Speed - Idle control stays in "Idle Recovery Mode" above this vehicle speed.
- Idle Recovery Duty - The value from this table is set when the throttle closes and is added to the idle duty to smooth the transition back to "Idle RPM Control Mode". Idle recovery duty is decayed at the rate set by the Decay Timer.
- Idle Recovery Timer - The idle recovery timer is set from this table based on the RPM when the throttle closed. Idle control stays in "Idle Recovery Mode" until this timer expires, or vehicle speed is below Min Speed.
IDLE ERROR
Idle RPM Control Mode
Idle RPM is controlled by incrementing or decrementing idle duty at an update rate that is based on
the RPM error (always positive) between engine rpm and target idle rpm.
Idle Duty Update Rate
When the idle rpm error is greater than Error Deadband, the idle duty update rate is set
as follows:
If engine rpm is LESS than target idle rpm :
If the rpm error is less than or equal Low RPM Error:
update rate = Low Error Update Rate,
otherwise
update rate = Med Error Update Rate.
If engine rpm is GREATER than target idle rpm :
If the rpm error is less than or equal Low RPM Error,
update rate = Low Error Update Rate,
else If the rpm error is less than or equal High RPM Error,
update rate = Med Error Update Rate,
otherwise
update rate = High Error Update Rate.
Anti-stall
If engine rpm falls at least 50rpm below target idle rpm , idle rpm low duty comp is calculated
based on the rpm error and RPM Low Gain. This is then added to idle duty, but
is limited to RPM Low Max Duty Comp.
Engaging the clutch slowly with the throttle closed, to creep along, causes the rpm to drop and idle rpm low duty comp is set raising idle duty. If the clutch is then disengaged, the rpm raises quickly and overshoots the target idle rpm. However idle rpm low duty comp has been set to 0, causing idle duty to drop quickly which could lead to oscillation. To prevent this, if the rpm is increasing greater than Rising Rate Deadband, half of the maximum calculated value of idle rpm low duty comp is added to idle duty to smooth the drop in idle duty under this condition.
- High RPM Error - Used in selecting the idle duty update rate.
- Low RPM Error - Used in selecting the idle duty update rate.
- Error Deadband - RPM error must be greater than this value to cause a change in idle duty.
- High Error Update Rate - See "Idle Duty Update Rate" above.
- Med Error Update Rate - See "Idle Duty Update Rate" above.
- Low Error Update Rate - See "Idle Duty Update Rate" above.
- RPM Low Gain - Controls the amount of anti-stall duty compensation when RPM is low.
- RPM Low Max Duty Comp - Sets the maximum calculated value of idle rpm low duty comp.
- Rising Rate Deadband - Sets the RPM raising rate at which idle duty is compensated to prevent idle rpm from falling too rapidly and causing oscillation.
IGNITION
Throttle Closed Ignition Timing Table
If enabled, the ECU uses the TPS CLOSED TIMING TABLE, based on RPM, to set the timing when
the throttle is closed, otherwise the active
IGNITION TABLE is used.
- Enable TPS Closed Timing - Enables using the TPS CLOSED TIMING TABLE for the ignition timing when the throttle is closed. If disabled, the active IGNITION TABLE is used.
- TPS CLOSED TIMING TABLE - If enabled, sets ignition timing based on RPM when throttle is closed.
See also ECT IDLE IGNITION TRIM.
- Enable Idle RPM Control Tables - If enabled, ignition timing is used to control idle rpm.
- RPM Control Min ECT - Minimum ECT required to control idle rpm with timing.
- RPM Control Max Error - Idle RPM must be less than this value above engine rpm to control idle rpm with timing.
- HIGH IDLE RPM RETARD - If engine RPM is above target idle RPM, the timing is retarded by the value from this table based on RPM error.
- LOW IDLE RPM ADVANCE - If engine RPM is below target idle RPM, the timing is advanced by the value from this table based on RPM error.
TPS OPEN DUTY
Throttle Open Idle Duty Parameters
Idle duty is controlled by these parameters when either the throttle is open, or is closed with
transmission in gear and vehicle speed above Idle Recovery Min Speed. In this mode,
if idle duty is less than TPS Open Min Duty, it is incremented at the rate set by
TPS Open Low Timer. If idle duty is greater than the value from the TPS Open Max Duty
table, it is decremented at the rate set by TPS Open High Timer.
- TPS Open Min Duty - If idle duty is below this value and the TPS Open Low Timer has expired, idle duty is incremented.
- TPS Open Low Timer - Sets the increment rate of idle duty.
- TPS Open High Timer - Sets the decrement rate of idle duty.
- TPS Open Max Duty - Values from this table set the maximum idle duty when the throttle is open based on ECT.
- TPS Open Min Duty - Values from this table set the minimum total idle duty when the throttle is open based on RPM.