Water injection improves MPG?

[cRiPpLe_rOoStEr]

Makes me wonder what would be the effects of either replacing the EGR flow entirely with some water injection for the sake of emissions control, or eventually adding a secondary injector specifically to cool it down a little further, since it's still quite hot even after going through the stock EGR cooler.

[stovie]

I was thinking of taking a 4 inch pvc pipe in a sideways v shape filled with water along the front of my bed with a line from the exhaust running through it and bubbling out the very bottom of the system and goes back to the top of the system through the water so that it becomes a egr cooler/filter/water steamer system for the car!?!

[ctmaybury@yahoo.com]

My 98 and 99 dodge diesels don't have egr, but I think the new diesels have water cooled egr. In my view, the egr is a poor smog control device. Maybe someone can educate me on the benifits. It cools the combustion therefore reduces the nitrogen oxides, but at the same time increases the hc output (aka unburned fuel). Eco mods should have the main goal of useing all the fuel you send through the motor. I see hc co2 and co as the main source of air pollution. It doesn't seem to me that no no2 no3 or whatever the nitrogen oxides that come out the tailpipe are constitute pollution. What happens to them when they get broken up by uv in the upper atmosphere? The free nitrogen or free oxygen will not be harmfull to anything. The chemistry might be beyond my understanding though.

[oil pan 4]

Yes EGR (on a diesel only) reduces power, fuel economy, warmup time and NOx, while it increases HC, CO and soot production.
I say if you don't live in a NOx and PM area then delete the emissions control stuff.

The worse part is the diesel particulate filter regen. Ford claims on their first generation of DPF equipped trucks that DPF regeneration can burn up to 17L of fuel.
I work with people who have newer dodge diesels and have deleted the emissions stuff, they said their fuel economy went from 15 to 20mpg up to 25 to 28mpg.

EGR on a gasoline engine is completely different, don't delete it. It normally gives you better fuel economy.

[teoman]

17L in how many miles or how much time?

That would be worth doing electric regeneration to burn it off.

[oil pan 4]

How ever long it takes the DPF to need a regen.
From what I hear the regen cycle it's self burns fuel very rapidly.
It's got to get hot enough to ignite the diesel soot and burn it off.

[ctmaybury@yahoo.com]

It seems to me getting as close as you can to complete burn is a better approach than throwing that much fuel into the exhaust.

[teoman]

Dayng, so if you have a 5 km commute and the dpf decides to do a regeneration consuming 17L for that trip your fuel consumption will be 340L / 100 km. Which is roughly equal to 0.7 mpg!!!!

[ctmaybury@yahoo.com]

I think city driving generates more soot therefore requires more regen cycles.

[oil pan 4]

Short trips are especially bad for DPF. Ford had DPFs get so bad the vehicle wouldn't run.
But it should take more than a single 5km commute to cause the DPF to need a regen.
If you use the diesel truck like a diesel truck, pulling a big heavy trailer over mountians and stuff the DPF fuel drain isn't as bad.