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Old 06-04-2008, 01:22 PM   #26 (permalink)
malc9141
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Default Re: Two stroke diesel: Build a simple ECU ??? Do-able, or not?

Estimating the capacitance of the capacitor.

The two-stroke engine fires each rev, and revs at 40/sec. Each shot of fuel lasts, say, 6 degrees (maybe less) of crank turn. ie 6/360 X 1/40 secs. [4/10^4]........u

Our current is 4 mAmp (we've been told), [4/10^3].......w

That current flows for the time stated, so it requires a charge of (amp X sec)
=uw or [1.6/10^6] Coulombs.

Charge (known) is proportional to volts (10^2) and capacitance (unknown).

Capacitance (C) in microFarads means multiplying by 10^6.

So, C = 10^6 times 1.6/10^6 divided by 10^2,

ie about 0.02 muF, which is convenient if true!

Conclusion, we use a 0.02 muF capacitor.

Malc
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