Quote:
Originally Posted by gotoluc
Hi Bob,
I would try to bring the timing closer to TDC or at TDC if it performs well there. The main reason timing is advanced on cars is the fuel energy is delayed from the spark. However the plasma spark maybe faster at converting the fuel energy so one should definitely be testing different timing positions and bring it all the way to TDC if it gives best economy. Leaving it stock you may not see any benefits while using the plasma spark or even losses as it will somewhat stall the piston movement if the fuel energy is before TDC.
You may also need to lock the timing advance mechanism.
Let us know of your result once you change things.
Luc
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Rich A/F mixture burs fast so old cars mechanical advance was set around 15deg.
Lean mixtures burn slow thus computerized ignition system produce spark up to 60deg BTDC.
Maximum cylinder pressure is obtained at TDC by heating the Nitrogen and Steam, a byproduct of combustion.
It is hard to control the burning process therefore, to take the advantage of heat produced by the plasma-steam at least two ignition points are required, One for the normal A/F ratio and Second at TDC (additional heat).
To take advantage of Pulse Detonation (interaction of water and plasma) ignition is required ATDC so that the Crank-Shaft- Rod geometry is not opposing supersonic pulse load.
Al