High Idle/Regen/Load/No load

Ok I am not a mechanic and no one has ever accused me of being the sharpest tool in the shed. But I have been catching up on several years of reading on this forum and I am confused.

I was thinking of retro installing a high idle option as Moby is nearing her 200K turn over and the wife does occasionally regular idle to keep the AC cooling. Texas heat, hot wife… does not mean good time in this case. So my quest began.

There are various opinions about high idling and if the high idle really helps keep the DPF clean because idling is not under load and therefore is not the same as driving at highway speeds which is under load. Highway speeds is what it takes…that is what we are told…running fast and free…that is what is good for Moby… keeps her DPF clean.

I am jealous of Moby cause I like running fast and free too, but I can guarantee wife would not agree. She says I need to stay home and keep it in park and low idle…tells me it keeps me safe and intact while I sleep…says this while she is chopping vegetables…I think there may be a hidden message in her comment… but I digress.

I dare ask….is high idling the same as manual regen? Every video I have seen on manual regen and from what I observed when I was at the dealership…manual regen seems to basically bring the idle speed up to 2K for 15-30 minutes. So, why would installing a high idle with the idle speed set at 2k be any different than a manual regen? Would it not be a good matter of practice to set your idle (using stick or high idle option) to 2K say at least once month after you brought your sprinter up to operating temperature? Seems to be a cheap option than paying a dealer $150+ to do a manual regen for me. Yes wife says I am a cheap date…but who can blame me $150 is a few gallons of diesel.

So am I just not getting it? What is the difference between high idling at 2K for 15-30 minutes versus manual regen?

Happy

Sprinter DPF regenerations require post injections of fuel to raise the temperature of the DPF to 1100° Fahrenheit. High idling does not initiate post injections.

Please note that idle sticks will not work on a Bluetec engine because the ECU will realize the vehicle is in park, not moving and will not allow for stable high-idle adjustment via accelerator pedal.

HVF,
No......absolutely not!
A full DPF regeneration requires the engine to be at least partially loaded, up to full operating temperature,
and hopefully running > 2500 RPM's.
Simply revving the engine with no load would probably PREVENT a good full temp DPF regeneration.
The high idle is meant to take care of other emissions issues (like intake manifold and swirl valve coking).
Your engine really won't develop full operating temperature, nor does the air flow through the engine get
any where near what it is when your engine is in the 70-80 % engine load range and pulling hard in the
22700-3200 RPM range that would give you the best overall DPF cycle.
Roger

As noted above, a regeneration requires very high EGTs (1100-1300F), which in the Sprinter is provided by post-combustion fuel injection during regeneration. Fuel is injected during the exhaust stroke and ignited by the glow plugs, then travels to the DPF and superheats the DPF substrate causing collected soot to be reduced to ash. This all occurs as part of the special regeneration cycle and is not even remotely duplicated by high idle.

In the Sprinter regeneration occurs at both preset intervals (based on mileage and fuel consumed) and/or of differential pressure in the DPF rises above a certain value. Certain conditions must exist for regeneration to begin but FWIW engine load and road speed are not among them, I have seen automatic regenerations start and complete while I was in stop-and-go traffic, never exceeding 30 mph and a light engine load. The engine load doesn't matter per se because the ECU maintains EGT at the required temp regardless, however while not absolutely mandatory it is preferable to have regeneration occur at higher speeds and loads because the additional exhaust gas pressure and velocity assists in purging the DPF, making the regeneration process more effective.

Or when someone tunes it and the PCM can't "see' DPF inf!
I have a MB engine d Jeep G/Cherokee with that issue in the shop at the moment.

This one had to have a new PCM to get it to read something.
Tune really dicked it up!
Dennis

As always, Smiller is spot-on. Well, mostly always. I want to avoid interrupting regenerations when safe and operate the vehicle at highway speeds until regen is completed. The increased, uninterrupted exhaust flow may help purge ash. It may be prudent to drive a bit longer to allow the oil/additives and heat process any fuel/crankcase oil contamination.

How about an ultrasonic DPF vibrator that can be activated during regeneration. Ultrasonic waves would dislodge ash from the DPF and swept away by the exhaust stream.

Thanks all for the information. Since Moby, MY2008, does not have the warning lights on the dash that say regen in progress-keep driving, DPF is beyond regen seek dealer help , of DPF is seek get a DPF delete tune...has any one installed some type of after market warning light system?

Any Scanguage or UltraGuage (aftermarket display that connects to the vehicle's OBDII port) can indicate when a regeneration is in progress.

Not very elegant or pretty solution, but a solution non the less