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Old 01-15-2020, 08:46 AM   #5 (permalink)
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What is the function of a fuel vaporizer? Is this to add fuel to the air charge before the injectors fire? I've been doing a lot of engine tuning lately and it seems to me this would wreak havoc on AFR.

At high load most ECUs go into open loop, meaning vaporized fuel would not be accounted for and an engine would go very rich (wasting fuel). Ideally you wouldn't have any added fuel at high load.

vacuum is highest at DFCO, when the engine wants zero fuel, and a system that's adding fuel at this time is just dumping it out the exhaust.

If fuel is added proportional to vacuum, it would make it difficult for an ECU to apply fuel trims at part throttle low load. Usually, different conditions cause a fixed (e.g. -3%, +5%) difference in fueling needs, be it from temperature, humidity, w/e, and an ECU will apply a fixed trim to correct this - except in open loop zones of the fuel tables. If added fuel is variable with vacuum, AFR would be all over the place while driving.

What is the function of a fuel vaporizer and how is it supposed to bring benefits?
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