View Single Post
Old 09-14-2018, 03:21 PM   #31 (permalink)
Stubby79
Master EcoModder
 
Stubby79's Avatar
 
Join Date: Sep 2012
Location: Victoria, BC
Posts: 1,747

Firefly EV - '98 Pontiac Firefly EV
90 day: 107.65 mpg (US)

Little Boy Blue - '05 Toyota Echo
90 day: 33.35 mpg (US)

BlueZ - '19 Nissan 370Z Sport
90 day: 17.19 mpg (US)
Thanks: 75
Thanked 576 Times in 426 Posts
I'd assume you need to use propane or CNG, due to the compression igniting said fuel...as far as I understand it, diesels inject at/close to TDC, so the power stroke starts then...if you have already introduced a fuel that will ignite before TDC, it will combust as soon as there is enough compression, before TDC, causing knock/detonation. Not good for your engine. Propane has a notably higher octane rating, so it is less likely to happen with it.

Also, from what I understand, "they" claim you get better mileage because you get better/more thorough combustion with propane mixed in, which is part of the reason you don't need to run a whole lot to get a benefit. While gasoline might vaporize well, I doubt it's anywhere near as thoroughly and evenly vaporized compared to a gaseous fuel, so it would not give as much of a benefit.

My thoughts (with no real proof) are that having a bit of propane mixed in effectively increases the compression the cylinder when it ignites, which in turn allows you to get more work(actual mechanical work/power out) out of the same volume of diesel injected. Less pumping losses effectively.


Last edited by Stubby79; 09-14-2018 at 03:27 PM..
  Reply With Quote
The Following User Says Thank You to Stubby79 For This Useful Post:
TDFbound (11-22-2018)