In section 7 (page 161), the figure shows a second injection of PCM (when TPS voltage is raising), in response of rapid power demand. Then pulse width increases (when TPS voltage is constant) in response of MAP change.
Is this second injection replicated in all cilinders during TPS rainsing or just in the one near to TPS raising?
Does the PCM change (or re-program) the pulse width of that second injection?
That picture was meant to be an illustration of acceleration enrichment not to speak on the real specific strategies of each system. In fact it may not even apply to ETC systems.
As far as all cylinders getting that extra shot of fuel in that capture, yes. All injectors would follow that same p.w. command at least to a point. It is only milliseconds later that all the cylinders fire. I don't think it would be altered much. Great question!
Transient enrichment in response to sudden throttle opening is hugely complicated, in the old times before emissions became an issue carburetors would dump a huge squirt of extra fuel into to counter extreme lean conditions caused by sudden throttle opening. At low RPM and throttle opening on a carb engine it is easy to understand how a lot of fuel previously mixed with air will have dropped out and formed pools on the manifold walls and be unavailable for combustion especially when the throttle is suddenly opened and the pressure increases from a fairly decent sized vacuum to atmospheric.
Even on a modernish efi engine that squirts fuel directly in the port a lot of fuel will be on the wall the manifold because there are continuous pulses of pressure in the inlet port as the valves open and close. This is the reason over the last 30+ years we have seen the trend has been to move from single point injection to port bank fired injection, then to full sequential injection and now to GDI as by doing this manufacturers have managed to get tighter control of the fuel/air ratio durring rapid movements of the throttle.
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(Walter Bishop Fringe TV show)
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