understanding the DPF with Techstream

[koji]

Or at least, trying to understand...

All regarding the diesel particulate filter (DPF) is a little bit obscure, so I'm trying to find some clues with your help, and the Techstream software.

Some questions to start with:

1) if the DPF regeneration is so important, why doesn't it show it in the panel while working? It seems you shouldn't stop nor idle your engine, so an icon in the display would help a lot...

2) how often does the DPF regenerate?, yeah, yeah, I know "it depends on...", but a general rule would help. Toyota Australia speaks about a range 150-400 km (https://toyotamanuals.com.au/docs/diesel-particulate-filter-dpf-information-booklet/). I thought it would be once in a year or each 10000 miles, but I see I'm wrong...

3) If the Techstream sees "PM accumulation ratio" parameter between 0 and 100%, how come some people get +200%? Is it a case of "overclogged" or not regenerated filter?

 

(more to come)

 

 

[koji]

a snapshot BEFORE regenerating the DPF:

2013 diesel engine, 60000 miles, very good maintained...😄

 

[koji]

and another snapshot, this time AFTER the DPF regeneration

(this was by pure chance the following day, I didn't know what was going on...)

 

different colours, but the same parameters

 

[solero]

My last diesel with a dpf would give off a burning smell, and fuel economy would drop instantly. They never tell you its doing a regen. About every 150 miles.

[koji]

After some research with the Techstream, it seems the DPF regens every 100-130 miles, depending on the amount of urban driving, and of course, the engine type.

I thought it would be more distance. This filter will work more than I expected...

 

What's the life expectancy of this DPF, according to your experience?

 

[solero]

3 hours ago, koji said:

After some research with the Techstream, it seems the DPF regens every 100-130 miles, depending on the amount of urban driving, and of course, the engine type.

I thought it would be more distance. This filter will work more than I expected...

 

What's the life expectancy of this DPF, according to your experience?

 

If it gets blocked, then a clean will rejuvenate it. It should last the life of the engine unless corrosion gets to it, or a hotspot burns a hole through it.

[Bper]

Hi Koji,automatic cleaning, DPFs trap soot but clean themselves through regeneration burning off soot at high temperatures. There's usually no dashboard light for this as it supposed to be seamless.Short trips and frequent Cleaning,and lots of stop and go driving creates more soot, requiring regeneration as often as every 100-130 miles in your case.  If you have Techstream, the PM accumulation ratio helps you monitor DPF health (0-100% normal). A reading above 200% indicates a potential problem. Regeneration cycles might not be fully cleaning the DPF, possibly due to short trips or faulty sensors. The filter might be very clogged from long term buildup of soot if regeneration hasn't been effective.In rare cases, the DPF itself might be malfunctioning, leading to inaccurate readings or reduced filtering efficiency.

Short trips prevent the natural cleaning process, passive regeneration and force the car to rely on a harsher method active regeneration, which can lead to clogging over time.  Following recommended maintenance and taking occasional motorway or perhaps higjway in your case runs can extend DPF lifespan generally 100,000-200,000 miles.

If you do see a reading above 200% ask a mechanic for diagnosis and solutions like forced regeneration or DPF cleaning/replacement. By understanding DPF regeneration and its link to your driving habits, you can keep your filter clean and your car running smoothly. Hope this helps.

[Mjolinor]

Whatever you do the DPF will eventually fill with ash that cannot be removed by normal means. It has to be washed out or dismantled and blown out or replaced.

The worlds most stupid idea ever are DPFs. On the plus side if you disable the EGR then little soot is made and the need for the DPF regeneration is seriously reduced, MPG is increased as is the life of the engine.

My Smart car has not regenerated for over five years and it only ever does runs under ten miles with an occasional (once a month ish) run to the autojumble 40 miles away.

 

[koji]

Thanks Bper, a very good explanation, it helps a lot.

Definitely, the parameter to watch in Techstream is "PM accumulation ratio" , under the engine ECU. It should remain under 100%, if not, there is a problem.

 

I'm not a tree-hugger, but I'm not disabling the EGR valve either. This is a very controversial topic, which would need a different thread in my humble opinion.