View Single Post
Old 01-15-2020, 08:46 AM   #5 (permalink)
Ecky
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: Vermont
Posts: 3,680

Gaptooth (retired) - '00 Honda Insight
Team Honda
Gen-1 Insights
90 day: 54.26 mpg (US)

Such Fit - '07 Honda Fit Sport
90 day: 41.27 mpg (US)

Connect - '15 Ford Transit Connect XL
90 day: 20.13 mpg (US)

K-sight - '00 Honda K-sight
90 day: 38.58 mpg (US)
Thanks: 1,424
Thanked 1,542 Times in 975 Posts
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?
  Reply With Quote