Quote:
Originally Posted by Softpatch
sorry for my question..
I'm still stuck in the "70's"
.(carb guy)
.
I was schooled that most US domestic cars Chevy/ford/Chrysler were Batch fired + means one fire all fire
Europe (german/Sweidish/GB/Italian) were sequentual fire Means specific injector fires during combustion stroke
.'
.
|
no, batch v sequential was always a processing power problem. the best Bosch EFI systems from the 80s and 90s (flapper AFM before MAF) were batch and its been theorized that GM borrowed heavily from this system in their original efforts.
Batch systems usually work in banks, so on a V8 2 batches of 4, a V6 2 batches of 6. Like I said, common sense would dictate that it shouldnt work efficiently that way, but it does, because the time between valve opening events at higher rpm is about 100 milliseconds and sometimes much much less. Air bounces in the intake as it waits for the valve to open, its never really stationary, so the fuel stays atomized and waits for the valve to open.
Imagine it as a prison break where the escapees are jumping through a turning fan with 4 blades. does it make sense for them all to rush for only one opening of the fan blades and simultaneously jump together? or to utilize all spaces between the blades? lets say that 4 can jump through simultaneously, even if the same number gets through the fan on every revolution using one per opening, which takes more planning and careful timing? Either way, 4 get through every revolution.
Now say you need more than 4 to get through every revolution, would you rather get four through every opening or try to get 16 through the one? this is the same problem with injector sizing for "one shot" sequential systems, you quickly overcome the ability of the injector to get enough fuel in the same window.
Now double the speed of the fan. Now quadruple it.