Belt-driving and a rotary encoder (going where no one has gone)
08-11-2006, 09:18 PM
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Belt-driving and a rotary encoder (going where no one has gone) I need to get one of these (or any high resolution rotary encoder really):
http://www.beiduncan.com/pdf/ex20.pdf (sorry only have PDF
)
Onto the belt-drive of a motor. I'm using a small block Chevy now, and an LSx later (3 months from now), but conceptually this shouldn't matter too much.
You think modifying the idler pulley to drive this would be the best way to at least attempt this? :dunno:
PS: Posting in this forum since if anyone has seen something like this before, it'd be for computer apps, and maybe something like this already exists on the market?
http://www.beiduncan.com/pdf/ex20.pdf (sorry only have PDF
)Onto the belt-drive of a motor. I'm using a small block Chevy now, and an LSx later (3 months from now), but conceptually this shouldn't matter too much.
You think modifying the idler pulley to drive this would be the best way to at least attempt this? :dunno:
PS: Posting in this forum since if anyone has seen something like this before, it'd be for computer apps, and maybe something like this already exists on the market?
08-12-2006, 01:16 AM
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Originally Posted by JoeyGC5
I thought MSD had a crank prox pickup assembly to do that? 
08-12-2006, 02:44 PM
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Can the computer you're using handle 200 pulses per rotation? Do you want that much resolution just to fire the spark and injectors, or something more sensitive like detecting misfires? GM only needed 28 pulses per rotation (I think) to detect misfires. I don't know why you'd want to mount it on the idler pulley, that wouldn't work if you're using it as an input to your engine computer.
Last edited by P Mack; 08-12-2006 at 02:55 PM.
08-12-2006, 02:58 PM
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Originally Posted by P Mack
Can the computer you're using handle 200 pulses per rotation? Do you want that much resolution just to fire the spark and injectors, or something more sensitive like detecting misfires? GM only needed 28 pulses per rotation (I think) to detect misfires. If you didn't attach it directly to the crank the extra resolution would be pretty much wasted in my opinion.
The computer I'm using has some weird limitations though. The way it does buffered outputs doesn't let me interpolate between reference pulses accurately. So with a 28 pulses per revolution trigger, it's either really inaccurate under certain conditions, or I limit myself to ignition timing always falling on one of the 28 ticks (completely unacceptable resolution).
It's a catch 22, other computers (for example, the Freescale MPC555) offer much better time interpolation abilities, but aren't even close to offering the processing power I need for another real-time thing I'm doing. This is to misfires what WB02 is to narrow band O2. :o
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08-12-2006, 03:25 PM
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Allen Bradley or Turck might be better suited for your needs then, with both better resolution and wider range of PPM abilities. Also why not machine a bolt on hub to front mount the resolver/encoder to the crank pulley?
08-12-2006, 03:51 PM
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Originally Posted by JoeyGC5
Allen Bradley or Turck might be better suited for your needs then, with both better resolution and wider range of PPM abilities. Also why not machine a bolt on hub to front mount the resolver/encoder to the crank pulley?
08-12-2006, 04:02 PM
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Man at this cost it's tempting to just bootstrap an MPC555 board. Run the core on the 555 and extra processing on the connected computer. This has to be the most disheartening project I've ever attempted.
08-12-2006, 04:15 PM
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The new Gen4 dev system from BS3 is another option I suppose since it supports custom interfacing with a computer (most systems I've seen only allow use of their proprietary tuning software).. do I even want to know how much that costs?
08-12-2006, 11:18 PM
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Originally Posted by P Mack
In that case there would be no point in running it off the idler pulley. The ecu would never know what the crank position is.
I think I found a solution to my problems: FPGA
08-13-2006, 12:25 AM
#16
So you are or you aren't using this sensor to determine crankshaft position? If you are, mounting it on the idler pulley will give you no useful information about the position of the crankshaft. You're posts are not clear at all.
What does that even mean?
Originally Posted by 280Z28
It doesn't need to know from that :o
What does that even mean? 