biodiesel and particulate filters

[Ivan]

Contrary to previous advice I received, that biodiesel is not compatible with diesel particulate filters (or at least, the process by which they work), this article suggests that biodiesel is beneficial for particulate filters:

http://www.greencarcongress.com/2006/08/biodiesels_bene.html

[stephen]

I wonder who starts the rumours that bio is bad.......

Stephen

[Ivan]

I think it was trying to explain why VW, after years of saying 'go ahead, our cars are great on 100% biodiesel' suddenly started printing 'do not use biodiesel' inside the filler cover, in addition to notes in the car manual (which I wasn't too pleased about - my wife having purchased one, with the intention of running on biodiesel or veg oil).


Ivan

[Bob]

The Volkswagen change may have something to do with the often poor quality of home-made bio diesel?  If someone buys a new car with a warranty and then gums up the engine because they have not been sufficiently washing the soaps out of the fuel it could prove expensive for them.

[Ivan]

My wife's car is one of the new VW Golfs. I really want to run it on biodiesel, but I just can't convince my wife, when it says 'do not use biodiesel' just inside the filler cap.

She lets me talk her into all sorts of things with the 'I know better...' but there's no way to get this one to stick unless I had scrapped the warning off before she filled it up for the first time (I don't need to worry about the statements in the car manual - she's isn't likely to read them!). So I've looked and looked to find something on the internet telling me it's safe to ignore their warning - but I can't find it anywhere.

[frank2]

ivan

i believe the particle filters are purged at intervals by the ecu
it over injects to torch the carbon particles away iirc
might biodiesel have a problem with that ?

frank

[Ivan]

I heard that it MIGHT BE (stress that it was someone's conjecture) that the late-firing to clear the particulate filter causes poorer burning in the combustion chamber, leading to gummy deposits on bore which causes glazing and ultimately leakage past piston. It sounds unlikely though (especially when we heard all that 'it won't run on unleaded' rubbish in the 80s).


Ivan

[frank2]

ivan

i think they,re blagging too 
but the world has got very litigatious (?) and they,re just covering their butts eh

frank

[PEMTEK]

After using biodiesel from 2 commercial producers I have not been impressed.

One glooped up my filters with wax an a cool night (I mean around 5c) and the car would not pull or rev due to fuel starvation. I pumped some from the tank and it seemed like it must contain large amounts of lard which is useless for biodiesel and glycerine was settling from it which alarmed me even more. I mixed the tank with a few gallons of dinodiesel and it went ok. I just cannot imagine how caustic this diesel must have been and how much damage it could possibly do. Alarm bells should of rang when the guys were offering me as many IBC's of glycerine as I wanted as they could not get rid of it...

Another tank of diesel from another supplier had another bizzare problem where everytime i stopped the car when stinking hot after a few minutes it would not start until I pumped and pumped the priming pump whilst turning over the car. After some messing I pulled a the return pipe off the diesel pump to find the diesel boiling in the pump.. clearly far too much methanol had been used or other solvent and had not been removed which was boiling and pushing the diesel out of the pump.

If this is anything to go by for other producers then it is easy to see why car manufacturers wouldnt advertise their cars as being biodiesel compatible and i certainly dont blame them. I am sure most of them are biodiesel compatible if it is made properly but from my experience of local producers I would not put their stuff in an diesel. One of these suppliers was actually supplying fleets of buses from a city... 

However.. I am in Hongkong at the moment and travelling to China traffic hell this afternoon, ALL the taxis here are LPG and i believe almost all of the buses are biodiesel or biodeisel blend powered so I guess they make it properly. It certainly seems to help over other cities I have been to around the world as considering I can see 14 double decker buses out of my window and countless identical taxis all on one section of 2 lane road and this is a SUNDAY!


Phil

[Ted]

Ivan, see this thread http://www.lowimpact.org/forums/viewtopic.php?p=839&sid=9bf81bbc0010091705489d15a87f245a

My understanding is that if the fuel is tested and meets the relevant diesel DIN standard then you can use it.

[PEMTEK]

Yes I would agree, from personal experience with biodiesel if it has just been made and not washed and methanol not removed etc it is horrible stuff.

Methanol itself causes nasty corrosion so it cant be helping things.

These commercial places theoretically can't sell their diesel unless its tested but it must not be policed well.

[Paulo]

Ivan,
Could VWs change in policy RE biodiesel be related to introducing common rail engines? It would seem that this advance in efficiency is not as tolerant to Biodiesel - apparently.
Paul

[Ivan]

Thanks for some useful insight, and a useful link. It would appear that there's a good chance that it will run on biodiesel.

The VW cars don't actually have common rail. I think it's kind of half-way between mechanical and common rail. The recommendation against biodiesel does seem to coincide with the new injection system.

My homemade biodiesel should be a bit better than the horror stories mentioned! My only barrel of biodiesel from a commercial supplier wasn't very good - it looked ok at the top, but as I got nearer to the bottom, there was a definite sediment - again, probably lacked washing/filtering.