Dodge/Chrysler NGC, Jeep, Viper Pattern

[Fred]

Firstly, we need a better name for this pattern! :-)

Secondly, here is a picture of it that I was linked this morning :



It looks to be fairly straight forward to write a decoder for, but I don't like these diagrams for credibility, so I'll need better information before I start. Preferably a photo of the disk(s) and/or a new time stamp log from a connected FreeEMS once I've written the logging code for that type.

Fred.

[johu]

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[Fred]

Thanks! So are these hall effect devices or what?

[johu]

Yes, it's hall effect. Crank pattern is same for 4, 6 and 8 cylinder engines with NGC. This includes 3rd gen Hemi. Camshaft pattern varies between engines.

2009 and newer V8's have different crankshaft ring with 58/60 teeth instead of 30/32 on older.

[Fred]

Small update on this:

Given that it's hall, and the layout of the pattern, it should be straight forward to do, logic wise.

The current missing tooth code, quite frankly, sucks, but once that's improved, this will be easy to do with some code reuse.

Keep an eye out for missing tooth performance improvements and bug me when you see them.

Fred.

[johu]

Source: http://ecu.zeeff.com/viewtopic.php?f=38 ... =150#p1744

Camshaft Crank Shaft Specs
Voltage Input Low Max .95 Volts Measured at 20 Hertz Maximun Turn Off voltage
Voltage Input High Min 3.65 V Measured at 20 Hertz Minimum turn On voltage
Input Hysteresis .70 Min 1.00 Nominal
Open Circuit Voltage 4.85 Volts Minimum 5.15 V Max
Max input Voltage 16 volts
Input Current 4.5 Min Milliamps 5.6 Max mA @5 V +or- 1%
Operating Frequency 0-5700 Hz 9500 RPM with 10 degree teeth 36 Pulses/Rev
@ 5700 Hz

Hall effect ...notches every 10 degrees...two missing notches and 2 fused notches 180 degrees apart.
The camshaft trigger is different and thats what distinguishes whether it's a four. six. or eight cylinder.. pretty ingenious I say.

[johu]

Two photos of NGC V8 pre-2009 camshaft tonewheel (aka reluctor ring or whatever you want to call it) after shipping via UPS. Author unknown, found via Google image search. Third picture (and overlay on first) by me but should be accurate. Yellow sectors mark location of holes. Camshaft keyway and red arrow point straight up when #1 piston is TDC. Crankshaft key is pointing then to 2 and afaik missing teeths of crank wheel are also at 2 o'clock then.

I think we're still missing exact info about how crankshaft and camshaft wheels are aligned against each other. Likewise info on which hole/teeth marks #1 TDC still needs to be confirmned.

I have engine to play with but without factory ecu to drive it will be limited to probing signals from sensors with Open logic sniffer and Saleae while turning it with starter or by hand. Plus it's 500km away meaning can't just walk in to garage and start working.

[Fred]

500 is a lot of km! If/when you do take a trace, attach the saleae file here for reference, please :-)

Dev will go like this:

1) Develop crank only decoder for this, test, confirm working.
2) Develop each 4,6,8 cylinder cam sync setup, test each, confirm each working.

IE, we can have an engine up and running on it recording real world data before we develop the cam sync stuff. I need to add a firmware feature to ease this situation and allow people without sophisticated tools to contribute meaningful data from their engines.

Fred.

[johu]

Chrysler changed to 58/60 tooth ring in 2009. Only pic of it I could find attached.

[Fred]

Just a standard 60-2 wheel, by the looks? Still Hall, or VR from then on? Same cam sync stuff or different?