Two-Stroke use cases

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Fred
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Two-Stroke use cases

Post by Fred »

From a decoder perspective we have three main cases:
  • Per cylinder (usually cam based)
  • Per revolution (crank based)
  • Per cycle (usually cam based)
For two-stroke use per-cycle is also per-revolution and crank based with a full pattern of 360 degrees. That is to say, the per-cycle 720 degree decoder setups are not used on 2 strokes.

Per cylinder, aka, distributor style patterns could be generated from the crank just as much as the cam, if not for the distribution of spark issue. On a two-stroke per-cylinder could only be done from the crank.

So, then, the following cases exist:
  1. Four stroke, cam sync signal, 720 cycle
  2. Four stroke, crank sync signal, 360 cycle repeated twice
  3. Four stroke, per-cylinder sync signal, 720/cyl-count cycle, repeated cyl-count times
  4. Two stroke, crank sync signal, 360 cycle
  5. Two stroke, per-cylinder signal, 360/cyl-count cycle, repeated cyl-count times
  6. Wankel, "crank" sync signal, 360 cycle
  7. Wankel, per-combustion signal, 360/rotor-count cycle, repeated rotor-count times
Currently the scheduler uses a 720 pattern to do its math even for a sub-720 decoder. I may need to change this to simplify 2 stroke and rotor use.

Fred.
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Fred
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Re: Two-Stroke use cases

Post by Fred »

Did I miss anything? Is anything wrong? Thanks for confirming and/or denying!

Fred.
DIYEFI.org - where Open Source means Open Source, and Free means Freedom
FreeEMS.org - the open source engine management system
FreeEMS dev diary and its comments thread and my turbo truck!
n00bs, do NOT PM or email tech questions! Use the forum!
The ever growing list of FreeEMS success stories!
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SleepyKeys
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Re: Two-Stroke use cases

Post by SleepyKeys »

I always thought of it like this for general pondering:
A cam sync signal on a four-stroke = a crank sync signal on a two-stroke.

"Currently the scheduler uses a 720 pattern to do its math even for a sub-720 decoder. I may need to change this to simplify 2 stroke and rotor use."
Cant you just multiply the *movent and keep the same back-end logic?

-sean
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