Location:
Ski, Norway.
(It would be nice if everyone gave a hint where they are located.)
Resources:
Microcontrollers and Realtime programming since 1984. Mostly support and making hardware drivers.
Have used AVR and WinAVR in a couple of recent projects at work.
Schematics and board layout.
Obviously no Wiki expert. ;)
Cars:
Alfa GTV 2.0TS. I think I'll leave this with the brain it has. ;)
Maserati Biturbo Spyder.
- Original ECU: Magneti Marelli IAW.
- It has a 2800cc 90 degree V6 engine with 2 turbo units (surprize!).
- One IHI RHB50 for each cylinder bank.
- The MM-IAW use separate injection and ignition ECU's.
- The boost control solenoid is controlled by the ignition ECU (Check) to a 0,7bar overpressure.
- Both ECU's are based on MC6801 + MC1442 (ADC) + MC6840 (Timer/Counter).
- Knock sensor located between cylinder banks, goes through HPF made up of LM2902 with gated output to ADC.
- It has an absolute air pressure sensor built into one of the ECU's (Check which of them).
- It uses 2 coils going into a distributor using a rotor with 2 separate fingers. They fire in succession.
- It has one crank sensor on the front with 6 unevenly spaced tabs on the pulley to time the events, and one cam sensor on the right camshaft to phase the spark events.
- The injection ECU has one analog channel for the Throttle Position Pot, and one input from the AC signalling when the compressor is enabled.
This engine is presently not in the car. It now runs with a 2500cc pressurized carb system. The 2800 is in pieces that are planned to come together this winter. Besides cleaning up ports and valve pockets, it is standard. There should be no reason to do anything internally. There are AFAIK only 2 common reasons for it to blow up: bad maintenance or not properly assembled. There is probably no sensible reason to not use the MM-IAW, but then I'm known not always to make sense. ;)
It has been established that the Maserati V6 engines are odd fire.
- exact angle of the trigger pulses is still unknown
- Be sure to describe when you get to know
An hopefully easy to understand example in engine degrees:
0 +90
90 +150
240 +90
330 +150
480 +90
570 +150
720
If we remove 360deg from all values >= 360 we get:
090
240
330
120
210
0If we interlace them and apply the 90/150 degree rule to the table:
0
90 (90-90=0)
120 ignore
210 ignore
240 (240-150=90)
330 (330-90=240)
0 ignore
90 ignore
120 (360+120-150=330)
210 (210-120=90)
240 ignore
330 ignore
0 (360+0-150=210)
90 (90-90=0)
120 ignore
210 ignore
240 (240-150=90)
330 (330-90=240)
0 ignore
90 ignore
120 (360+120-150=330)
210 (210-120=90)
240 ignore
330 ignore
0 (360+0-150=210)
90 (90-90=0)
We find that we want to ignore two triggs and then act on two triggs. We also see the 30/90 pattern in the triggerwheel that can be used to update rpm. This definitely can be done without stabilizing the trunk code, applying some code in multitooth.c.
Some thinking also show how the Buick odd fire engine can be run with wastefire! As usual with waste fire grouping we take the Buick fire order:
1-6-5-4-3-2, write on two rows:
1-6-5
4-3-2
The columns are grouped on each wastespark coil. Adding 90+150+90give us 330 degrees betweeen #1 and #4 TDC's and that means that #4 is 30 deg BTDC in it's exhaust stroke when #1 is in compression TDC. That should be ok. Counting the other way around starting from #4 compression TDC give 150+90+150=390 which would indicate that #1 is 30 degrees into it's intake stroke when #4 is at compression TDC. I get a feeling that late timing might be bad as if we were to fire at TDC the #1 cylinder would start to fill up with fresh mixture!
- IF COIL ON PLUG IGNITION is used you can even trigg it with only a multitooth crank trigger!
- is cam-trigger not available ?
- If waste fire was to be used the cylinder that has an early twin would be fired at the right time and 60 degrees too early!
- For odd-fire V6, I never heard of pairing cylinders using 3 transformers in wasted-spark configuration. Even if we cannot find such references, it doesn't mean that it cannot be done. However, there are too many uncertainties with it: if possible, cam+crank+COP would be the straightforward way to go.
Einar (Spamcheck-AT) Sjaavik (Spamcheck-DOT) com
check out ChatViaIrc and come there and chat with us... //Emil Larsson, Sweden
Thanks for the invitation. I may try that. Is there any time for "club meetings"? It seems to me a small group like this it would be difficult to meet someone just by chance?
OK. I admit I was wrong. It was not difficult. @Emil: The engine I mentioned is a B230ET from a 940.