mr. ed

Ok, here's another question for you guys. My truck is completely stock. I have not at this point installed a pyrometer (EGT gauge). Is there any way to tell that the engine is regenerating, perhaps by the coolant temp gauge or by noticing temporary mileage reduction on the overhead console? I've been traveling pretty extensively lately towing a fifth wheel trailer and think I noticed a fluctuation in mileage that was out of the norm, according to the readout. Perhaps these were the times it was regenerating? Thanks in advance for your input....Ed

sleds

If you watch your overhead, your mileage will go in the toilet when it's doing a regen. When mine is doing a regen it will get 13-14mpg where normally it would say 18-20.

upnorth

It seems excessive to experience a 5 mpg penalty during a regeneration but I don't know and maybe you're right. How much fuel does a regeneration burn ? How long does it take ?
When required, and other event from the injector is squirting fuel at the exhaust stroke to raise the temperature of the exhaust to turn the soot into ashes in the DPF. Where is the fuel burnt ? after the Turbo ? With the EGR valve, does a portion of that fuel with a portion of the exhaust gas go back to the engine ?

59 cmnz

When mine has gone into regen, my mileage drops approx .1 mpg every couple of minutes and lasts about 10min total.

i6epoolguy

Good questions upnorth. I would like the answers to those questions myself,
just to have a better understanding of exactly how the system works. I know mine has probably regened,and I can't tell when. You can't tell by the performance, and it has never sounded differant to me.

Krazeeun

I just finished up a 3k trip from NW florida, to michigan, around michigan, then to south FL... then back to NW FL.. I cruised at 75mph the entire time on the freeway (except for contstruction)

I traveled w/no trailer & a truck full of passengers, overall hand calc tank avg's was 16.4mpg. The overhead is pretty close to hand calc'd as long as you reset the overhead as soon as you top off & dont touch it again until you fill up again.. mine was on avg .4 off from actual.

The overhead unit is off a bit because my stock speedo is off according to my GPS. My gps says i'm doing 75 while speedo says i'm doing 77-78

I DID notice a big gouge in mileage about once a tank which i assumed was the truck doing a regen.... overhead would say very low early on (8-9)mpg from idling at fuel station & taking off.. then climb nicely to around 18-19.. then hover there for a while, then take a dip down into the 14 range quickly, then pick back up to around 16.5-17 by the next fill up

I filled up every 300-400 miles, according to overhead I can go 615 miles on a tank...

Krazeeun

I'd like to add to that last post..

In the hills of kentucky/tenn I was messing around with trying to see how effecient the truck was once under way & kept resetting the overhead at different speeds to see what it did

if I reset it with the cruise on @75mph(according to gps not speedo) it would hover around 19.5

I got the best numbers in the big hills where I coasted down & powered up, avg'd 21mpg according to overhead over about a 100 mile stretch...

k.. sorry, back on topic fellas

upnorth

We might have to start new threads to get answers to those questions ???
Go for it i6epoolguy ...

bigblock2stroke

If he reset his overhead when he went into regen, 5mpg would be about right. But averaged over a "fill up" it should only be about 1/1.5mpg.

These questions are difficult to answer. The amount of extra fuel required to do the regen is a function of many variables (engine duty cycle, how heavily the dpf is being loaded with soot, and ambient conditions).

regen time is also a function of these variables. However, my experience is that a normal dpf regen takes about 30 minutes of steady state vehicle speed anywhere above about 40mph. If you stop/go, it will take longer (as the system cools when you are stopped and then takes time/fuel to heat back up).

when you are doing active regen, the egr valve is held closed to keep fuel from getting back in.