124 lines
6.6 KiB
Markdown
124 lines
6.6 KiB
Markdown
# Reverse Engineering Saab Trionic 8 Combustion Detection Module (CDM) output signals using rusEFI ECU
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***by Andrey Belomutskiy, 2018***
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* Table of contents
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* [Overview](https://github.com/rusefi/rusefi_documentation/tree/master/Misc/Saab_Trionic_8_Combustion%20Detection%20Module_on_Mazda_Miata_running_rusEFI#overview)
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* [Hardware](https://github.com/rusefi/rusefi_documentation/tree/master/Misc/Saab_Trionic_8_Combustion%20Detection%20Module_on_Mazda_Miata_running_rusEFI#hardware)
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* [Detonation test scenario](https://github.com/rusefi/rusefi_documentation/tree/master/Misc/Saab_Trionic_8_Combustion%20Detection%20Module_on_Mazda_Miata_running_rusEFI#detonation-test-scenario)
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* [Detonation signals](https://github.com/rusefi/rusefi_documentation/tree/master/Misc/Saab_Trionic_8_Combustion%20Detection%20Module_on_Mazda_Miata_running_rusEFI#detonation-signals)
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* [Next Steps](https://github.com/rusefi/rusefi_documentation/tree/master/Misc/Saab_Trionic_8_Combustion%20Detection%20Module_on_Mazda_Miata_running_rusEFI#next-steps)
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* [External links](https://github.com/rusefi/rusefi_documentation/tree/master/Misc/Saab_Trionic_8_Combustion%20Detection%20Module_on_Mazda_Miata_running_rusEFI#external-links)
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This data would not be gathered without help from kb1gtt, stefanst, andreika, nighthunter, hankthefourth and many others.
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**In this report we show how detonation on 2003 Mazda Miata MX-5 could be detected by means of ion sensing using Saab 55352173 Combustion Detection Module (CDM) and H6T60271 Individual Ignition Coils**
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## TL;DR
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knock and combustion detection outputs of 55352173 are digital. Knock is reported with a series of 50us pulses, more pulses
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meaning more detonation. Combustion signal seems to be just a comparator giving logical true if ion sensing wire voltage is below certain level. First wide pulse on the combustion output seems to be flame front phase while second wide output
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seems to be showing post-flame pressure, with the middle of this pulse correlating with moment of peak cylinder pressure.
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Knocking - note a lot of blue line pulses (1ms time base)
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Knocking (50us time base)
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Not knocking or knocking way less - note lack of blue line low level pulses (5ms time base)
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Combustion signal seem to be just a comparator
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[All the videos mentioned here](https://www.youtube.com/watch?v=1y1dXTg9iMg&list=PLwj_BUeepTNB6eddVd7_KtyqiFYOJ75jy)
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## Overview
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While Saab Trionic systems were using ion sense forever, only the latest eighth generation
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uses individual ignition coils and external CDM. Prior to T8, a highly integrated ignition cassette was used which would
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make repurposing it for DIY applications harder.
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Trionic 8 system does not have camshaft position sensor or knock sensor with combustion detection module running on ion sensing
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signal from ignition coil producing both phase and detonation detection.
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More recently, Mazda and BMW seem to be using ion sensing approach again.
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### Hardware
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Here are all the Saab components we will be using (only two coils pictured while four coils would be used)
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Ferrari 124792 spark plug extension is used to connect original Mazda Miata spark plugs with bullet terminals removed with Saab COPs
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[youtube: Hardware Details](https://youtu.be/rUZ_-_hRnDU)
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[youtube: Hardware Overview](https://www.youtube.com/watch?v=1y1dXTg9iMg)
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Knock detection wire has 0.8KOhm pull-up to 5v, combustion detection signal has 5KOhm pull-up to 5v.
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### Detonation test scenario
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2003 Mazda Miata 1.8 VVT Automatic running on rusEFI open source ECU.
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Engine coolant temperature 100C, ambient temperature 4C, violent 40 degrees advance from 1500 RPM to 3500 RPM timing table.
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Detonation is audible in 2000-4000 range with 50% throttle pulls from parked.
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Detonation is also audible while parked, revving with brakes applied in "D" gear selector.
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[youtube: It's knocking!](https://youtu.be/FQ9ii0eXjmA)
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#### Detonation signals
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[youtube: Four signals we see on the oscilloscope](https://youtu.be/7aafaZgr2AE)
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[youtube: No detonation while driving - baseline](https://youtu.be/2fNrJ7NDFm8)
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[youtube: Knocking while driving](https://youtu.be/eehx5zH8igI)
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[youtube: Knocking while driving zoomed in](https://youtu.be/QXTaa1mGbwE)
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[youtube: Knocking while standing on brakes 40 degrees timing](https://youtu.be/ylvMqOD50bY)
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[youtube: No knocking while standing on brakes 25 degrees timing](https://youtu.be/jS3LXw_v9ls)
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And that's it! We have seen enough to get some code for the rusEFI firmware to start consuming this knock signal data!
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### Next Steps
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1) Produce same outputs without CDM module
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2) Try Mazda H6T61171 ignition coils - these are a bit longer and narrower, seem to fit my Miata engine.
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3) analyze [raw waveforms](Misc/Saab_Trionic_8_Combustion Detection Module_on_Mazda_Miata_running_rusEFI/saab_cdm_2018_01_05_miata_rigol.zip) and detect knock based on just ion sense signal without CDM
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Inside of 55352173 Saab Ionization Detection Module
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### External Links
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[rusEFI Patreon](https://www.patreon.com/rusefi)
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[rusEFI ECU](https://www.rusefi.com/)
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[rusEFI forum](https://www.rusefi.com/forum/)
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[rusEFI store](https://www.shop.rusefi.com/shop)
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[Trionic 8](https://en.wikipedia.org/wiki/Trionic_8)
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[Saab 9-3 wikipedia](https://en.wikipedia.org/wiki/Saab_9-3#Second_generation_(2003%E2%80%932014))
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[Spark Advance Modeling and Control](http://www.fs.isy.liu.se/Publications/PhD/99_PhD_580_LE.pdf)
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