Firmware and MegaTune patch for 1.0.23 - ALS, Launch control, Soft revlimiter, etc
With this modification, the current ALS code reworked a little to meet racer's needs. Several options implemented, whose you see only on expensive professional systems before. Take a look to the setup window:
Let me explain the config variables:
Global settings
- Low RPM: ALS (retard, enrichment, spark-cutting) is disabled below this rpm to avoid engine stalling (you don't need this on a working system, only while experimenting). Suggested value: near your idle RPM without enabled ALS. Easy to misunderstand this. ECU will NOT try to maintain this "low-RPM" . ECU simply disables ALS below this RPM, which - depending on ALS setup might or might NOT result in maintaining this RPM. Eg you might not supply enough air to reach it and than RPM will be below this low-RPM. Not reached in normal operation (RPM kept above this; only to make engine-stall in strange conditions less likely)
- Deactivation time: ALS disabled after the specified interval. Suggested value: 5-15 seconds. set always!
- Deactivation EGT: ALS disabled if exhaust gas temperature is over the specified limit. Suggested value: 800 degrees Celsius. (under the melting point of your exhaust system material...) set always!
- Reactivation Minimum TPS: After deactivation (time elapsed), you only need to open throttle wider than this value to re-activate the ALS. Suggested value: 70-80%. Always set this higher than all 'Decrease end TPS'-es!
- Fuel enrichment: The fuel surplus while the ALS is active. Suggested value: 15-25%.
- Throttle kicker solenoid: Define an output channel if you have one (always-open-throttle-racecar-owners simply disable and forget this option :-) ). The firmware automatically release the TKS if the conditions disabled the ALS, even the ALS switch is on.
Igniton retarding and spark cutting is done as seen of the figure:
Note: the horizontal axis is labelled TPS, don't think that is RPM!
Ignition Retarding
- Maximum retard: The maximum ignition retarding value needed when you release the pedal. Suggested value: The highest ignition advance value plus 5-10. Zero disables retarding.
- Decrease start TPS: The maximum throttle opening you want to use the maximum retard. Suggested value: The TPS value you read with active throttle kicker plus 10-20%.
- Decrease end TPS: The minimum throttle opening you don't want to use ignition retarding. Suggested value: Set the minimum throttle where the engine can produce the desired boost. It must be 40-60%, or you need to re-think your engine implementation. If you set this too low: the turbo lag will be bigger. If you set this too high: the engine will be too weak.
Spark Cutting
- Maximum cut level: Percentage of sparks to be 'cut' (dismiss the event). The maximum ignition cut value needed when you release the pedal. Suggested value: 20-30%. Zero disables spark cutting.
- Decrease start TPS: The maximum throttle opening you want to use the maximum cut level. Suggested value: Simply set the TPS value you read with active throttle kicker. Add more 5%, when needed.
- Decrease end TPS: The minimum throttle opening you don't want to use ignition retarding. Suggested value: 10-20% bigger than start TPS.
You can enable ALS functions in my_make:\nÿ1ÿ
Override default maximum 20 degree ATDC limit:\nÿ2ÿ
The patch contains implementation of three new soft revlimiters. Soft revlimiters cut spark instead of cutting fuel if the desired maximum rpm are about to beaten. These are used for idle control, launch control and redline control. Idle control is TPS sensitive, and disabled, if ALS enabled and working. Launch control can be enabled with a button on the steering wheel, and it can be combined with the ALS. Redline control is for normal overrun protection without unsafe lean run, which is essential for the turbo engines. All (soft)revlimiters in one window:
And there is a little explaining about these.
Idle control
Used on racecars, where no other methods (IAC stepper, PWM solenoid) can be applied, especially where always open throttle is needed. The main function is to limit the rpm on a reasonable low range, when the pedal is depressed, and ALS is not active. See the figure.
- Enable: Enable or disable sparkcut based idle control.
- Minimum RPM: The operational range starting rpm. Suggested value: 800-1000.
- Maximum TPS: The maximum TPS where the idle control allowed to operate. Suggested value: The idle TPS value (0% in normal case), or add more 2-3%.
- Control range: The operational range. Suggested value: 200-300.
You can enable spark-cut based idle control in my_make:\nÿ3ÿ
Launch control
Used on start line, to achieve best performance with the less effort. Driver must press gas pedal to 100%, and press a button on the wheel. Launch control routine need to limit the rpm into a desired range, while the button pressed, and allow ALS to work (ALS normally disabled on so high TPS). See the figure how it is achieved:
- Minimum RPM: The operational range starting rpm. Suggested value: The highest torque rpm, or whatever.
- Control range: The operational range. This one can be set via the control range of the redline control. Suggested value: 200-500.
You can enable launch control in my_make:\nÿ4ÿ
- TODO: How to configure button input
Redline control
Simple sparkcut-based revlimiter, used below the hard RPM limiter, as you see on this figure:
- Minimum RPM: The operational range starting rpm. Suggested value: Hard rpm limit minus the control range.
- Control range: The operational range. Suggested value: 200-500.
You can enable launch control in my_make:\nÿ5ÿ
If you are understand and accepted the warnings generated in compile time, when using SOFTRPM based new functions, you can disable them with the following line in my_make:\nÿ6ÿ
Fero's ALS related suggestions
- under testing in stable1_1: +64 -64 degs of ignition window
- DONE in stable1_0: The retard degrees should be set from 0 degrees, instead of the actual ignition table setting.
- HMM: We could not confirm this: idle mode. It's important when using always a little opened throttle plate for extra air. So than the ECU holds the idle RPM via soft idle ignition cut. When the ALS is turned on than the ECU should be in ALS mode until the time limit is reached, even if TPS is 0% ! When the time limit is reached, than should be go into idle mode and hold the idle RPM. If i understand good, now the ECU turns off ALS if the TPS is 0%.
- no, it does not turn off ALS, it turns off the throttle kicker activation (when TPS released). It will leave throttle kicker on , see below
- DONE: Solenoid open all the time, when ALS switch is on. Solenoid is only switched off if any safety variables exceeded.
- POSTPONED: Solenoid PWM current limiting for high current solenoids.
- POSTPONED: smooth RPM range at the low RPM settings, (so ignition cut and the retard changes back smoothly). low-RPM is only a safety feature, not reached in normal operation.
How to disable ALS
The below config snippet (variables directly available since 1.0.32) disables ALS: (and kpa_conf configures reasonable unit for KPA-pressure related variables, 2 kPa for kpafac and 1 kPa for other variables including the k[] bins). kpa_conf=22 applies for the high-boost megatune profile (config units is 2kPa everywhere), for an engine that needs further retard and VE-increase above 256 kPa MAP (with this, engine mappable upto 510 kPa, above which further retard or VE-increase is not possible, but injector pulsewidth will continue to grow proportionally with even higher MAP of course).\n
als_cut_maxtps=00 als_cut_mintps=FF als_deact_egt=00 als_deact_rpm=FF als_deact_time=01 als_enrich=00 als_max_cut=00 als_react_tps=00 als_retard=00 als_retard_maxtps=00 als_retard_mintps=FF als_tks_channel=FF als_rev_limit=40 ign_balance=00 kpa_conf=21
Here is the quick path to start upgrade from a pre-ALS firmware to an ALS firmware. This minimizes the chance to get bitten by serious unintentionaly retard accidentally activated.
- save the above config snippet as config.txt
- save the (Man)mct dump to etc/mct.txt
- save the (Man)mcd dump to etc/mcd.txt (these will not have als_.. variables since you've started from a pre-ALS firmware)
- run make mtt (make_config.bat or whatever. It effectively runs perl bin/make_conf.pl global.h etc/config.txt etc/config.mtt command
- Any value in etc/mcd.txt will take priority over etc/config.txt
- TODO: verify if wintools notices etc/mcd.txt and uses the values to override the etc/config.txt
- save the error/output and examine any variables with warning or error
- upload etc/config.mtt to the ECM
Uploading the tables is similar (although it can be done from MegaTune - Remember to use a recent MegaTune for the ALS firmware):
- perl bin/make_tables.pl global.h etc/config.txt etc/config.mtt command
- upload the etc/tables.mtt