Quote:
Originally Posted by tasdrouille
I did it the other way around, added more boost for any given injection quantity through a simple bleed in the pressure line to the ECU. FE went down, probably due to higher back pressure from the VGT vanes.
Fuel in my TDI is being recirculated to the tank. At operating temps the fuel sensor in the injection pump reads around 50 C. I doubt there would be much to gain.
Fuel in a diesel does not evaporate, it atomizes and the small droplets burn. Lean mixtures in a diesel generate lower EGT. Never heard of pre-detonation. how can it predetonates without fuel? Fuel is injected right when it needs to start burning after a very short delay.
Off course I'm talking about a VW TDI with a VGT turbo. If you have a mechanical IDI with a wasgated turbo things might be different a bit.
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Thats clever.
I'm not sure if diesels do this but GDI does, they have stages of fuel injection for just the reason I mentioned.
Fuel layering allows you to continue to compress the mixture further before heat induced ignition. Its pretty simple and pretty ingenius.
Compres mixture gets hot, inject fuel, ignition.
Fuel Stratification
compress mix gets hot, inject fuel earlier, compress further than in example A, inject, compress, inject, ignite.
Use the same amount of fuel just inject slightly earlier to allow the fuel to evaporate and drop mix temps enough to avoid ignition and allow for further compression at lower octane rating(for gas).
If your diesel doesn't do this the next model year will. If your car/vehicle does this do not increase fuel temps above native temps, otherwise you are impeding your engine.