Diesel fuel additives for modern diesel.

**CardinalSin** · 08-12-2014, 11:39 AM

Originally Posted by Diesel_vert

Certain metals are known to improve the combustion of diesel fuel. Of these, iron, cerium and platinum in particular are used as fuel borne catalysts (FBC) for the regeneration of DPFs.

Ce-Pt FBCs have the effect of lowering the soot oxidation (regeneration) temperature, which is useful for vehicles that frequently encounter low load conditions (e.g. city driving).

Metallic FBCs are impratical at high dosages due to unacceptable levels of ash loading and exhaust back pressure. They are also not recommended for use in vehicles without a DPF due to concerns about metal oxide particle emissions (which the DPF would otherwise collect and prevent its release).

OEMs are aware of the advantages and disadvantages of active (fuel enrichment or additive/FBC) and passive exhaust aftertreatment systems. Literature on the subject, produced by research institutions and industry, is extensive.

Ce-Pt FBCs may help if the vehicle is experiencing extended problems with DPF regeneration.

Thanks for your informed reply which made sense to me.
To sum it up, would it be reasonable to advise to only use an additive like this if problems are occurring with the regen of the DPF and that regular use will add extra particles to the DPF and reduce it's life since they can't be burnt off?

**Transporter** · 08-12-2014, 06:15 PM

Penrite's instructions for use should be clear enough to most people, but I will just copy the text from the DPF Cleaner label.

* Add 375ml to 30L of diesel fuel for regeneration assist on 1st stage filter blockage (Warning light).
For blockage prevention & maintenance add 375ml for every 60L of diesel fuel every 5,000km.

I will take the Penrite's instruction any day and every time over your or someone else speculation.

I monitor very closely our 4 TDI cars with the DPFs and despite they're driven under severe driving conditions the DPFs aren't negatively affected and I expect they should last over 200,000km.
So, I will continue to use the DPF Cleaner every 5,000km and the Diesel Fuel Additive at every fill up, because that's the best practise to assure the longevity and the reliability of the diesel engine.

**CardinalSin** · 08-12-2014, 07:22 PM

I'm interested in this product because if all the claims are correct then it's worth using but I like to see actual results.

How do you monitor the affect on the DPF and how long have you been using it? Have you had any positive results such reduced particle loading and improved fuel economy?

**Transporter** · 08-12-2014, 08:21 PM

I use scanner to monitor the DPF. It's hard to notice any improvements in the fuel economy when you use the additive 100% of the time from new. Obviously I don't drive all 4 cars, so I don't recall that any of family members would comment that the engine was doing something strange (regenerating). The tail pipes are sparkling clean.
The fuel economy is always calculated from the docket and is very consistent over the years. Our Touareg done almost 110,000km, the DPF sensor failed at around 65,000km but it was replaced almost immediately, so no harm done to the DPF

.

I could check when exactly I've ordered the first lot the DPF Cleaner, but from top of my head probably between 9-12 moths ago. Prior that I've used the JLC additive once a year (very expensive).

**Diesel_vert** · 08-12-2014, 08:22 PM

Originally Posted by CardinalSin

Thanks for your informed reply which made sense to me.
To sum it up, would it be reasonable to advise to only use an additive like this if problems are occurring with the regen of the DPF and that regular use will add extra particles to the DPF and reduce it's life since they can't be burnt off?

There are several factors to consider.

Soluble forms of catalysation (such as fuel additives or FBCs - i.e. liquids) are more effective than coated substrates (solid catalysts) used in passive systems in accelerating oxidation rates, but by nature accumulate more easily in the substrate (obviously).

The reduction of soot formation from improved combustion characteristics via metallic fuel additives is offset by an increase in ash loading. The reduction in oxidation temperature via FBCs is also offset by an increase in ash loading.

The optimum treat rate may differ for each product. Too little may not unduly load the DPF, but its influence on soot formation or oxidation temperature may be ineffective. Too much may unduly reduce the DPF service life with no further improvement in oxidation rates. I do not have the time and resources to do anything apart from following the instructions on the label.

(One method of controlling the dosage is via an integrated additive system, such as that used by PSA Peugeot Citroen, which allows precise treat rates based on live information feeds from the engine ECU or sensors - with the aim of maximising FBC effectiveness with minimal ash loading. However, this adds complexity and cost).

Higher passive regeneration temperatures promotes a more thorough cleaning, at the cost of the DPF durability due to thermal stress - specifically, the silicon carbide substrate, through accelerated ageing. Malfunction of the post injection fuel delivery or uncontrolled regeneration can lead to cracks in severe circumstances. Not usually an issue for vehicles functioning as intended and without abnormalities.

It is important to note the timeframes, when dealing with this subject, are in the order of several tens of thousands of kilometres.

As stated, research literature on the subject is extensive. Perusing the internet should bring up a more through analysis than my amateurish findings. I'm sure there are other factors that I've skipped or missed and there is plenty of objective information available (both academic and industry research) than I care to admit to understanding in full.

As with anything that has multiple inputs and outputs, analysing and calculating the optimum cost to benefit ratio on a completely objective level can be quite demanding and complex, especially without the time and resources (expensive looking measuring equipment, especially) available to OE manufacturers, research institutions and industry.

If a vehicle with a passive exhaust aftertreatment system had extensive trouble undergoing regeneration, then using a Ce-Pt FBC may help accelerate oxidation rates with the aim of reducing exhaust back pressure, on a temporary basis. Such a vehicle would also be a candidate for in-depth fault finding, as this condition would be considered abnormal.

EDIT - I know my posts seem indirect, but I cannot really recommend a specific course of action, unless I know all (which I don't). I think the next best alternative is to list known pros and cons (or at least provide a few pointers on where others can start their own research), so members can arrive at their own conclusion based on their needs and requirements, acutal or perceived.

I have said once before that fuel additives are an essential component of the fuel "life cycle". Additives added at the refinery stage are an industry accepted practice and usually causes few issues. Controversy or disagreements usually arise (mostly on internet forums) from the use of aftermarket additives, specifically when added during the stage where fuel has left the terminal, but before entering the vehicle.

**CardinalSin** · 08-12-2014, 08:40 PM

Thanks for the details.
Assuming they aren't all less than a year old can you compare the particulate loading before and after for the Touareg and whichever of the others are over a year old? The same with fuel consumption?
If the increase in the particulate loading is less since using it and the fuel consumption is about 4%[half the max of 8%] better then I will happily give it a go and see what results I get.

Am I right in saying I can't use a scanner on mine because the ECU is locked and only accessable to Skoda? If I can I'll get one and check that too.

**CardinalSin** · 08-12-2014, 09:25 PM

Originally Posted by Diesel_vert

There are several factors to consider.

I had read this as meaning the particulates building in the DPF would be reduced by 20% but since it's only being used every 5,000km it must be referring to the cleaning effect improving combustion, reducing soot and therefore particles by 20%.?

"DPF Cleaner reduces engine particulate matter by up to 20% with ULSD(Ultra Low Sulphur Diesel) and 30% with B20/ULSD(Bio / Ultra Low Sulphur Diesel), so there is less soot(which when burnt accumulates as ash) to collect in the DPF."

It does claim the metals used leave a coating on the combustion surfaces and also coats the DPF. Perhaps that's where the continued 20% particulate loading comes from too?

"The active metals work synergistically to oxidize the soot particles and to regenerate and maintain a catalyst coating on the diesel
particulate filter with regular use."

"The combustion chamber surfaces are conditioned with active metals to promote a uniform flame front throughout the combustion cycle. This allows a faster burn at lower temperatures and also improves engine efficiency."

The proof of the pudding is in the results it achieves. If the rate of particulate loading isn't reduced and the fuel consumption remains the same it's a waste of time unless you need to force a regen for some reason.

**Transporter** · 09-12-2014, 06:32 AM

Originally Posted by CardinalSin

The proof of the pudding is in the results it achieves. If the rate of particulate loading isn't reduced and the fuel consumption remains the same it's a waste of time unless you need to force a regen for some reason.

I don't have a time to record all data every time I connect the scanner to the vehicle, but in incoming months I will get some life data from those that use the additive all the time and to those who don't, incl. the DPF Cleaner in some TDIs. Of course it will be far from 100% accurate indicator whether it has any impact on the DPF, since many conditions will be different and I wouldn't know how the car was driven.
But, I can tell right now that my observation is, those who use it? Very rarely have any fuel related problems and sometimes are unaware that there are any DPF problems.