Discussion in 'Other Cars' started by cwerdna, Mar 29, 2009.
UK supermarket starts selling B30, manufacturers advise customers not to fill-up
I certainly wouldn't advise putting it in a Prius
Biodiesel suffers from the same problem as ethanol. There's only so much 'waste' material available. Once you get into growing new crops to produce your feedstock, you have to account for how you got it. Western farming is energy-intensive, some estimates have 100 times as much energy (or energy equivalent) goes into producing the crop as the actual energy value of the crop itself.
That's not to say that we shouldn't make best use of the waste, as long as the energy to convert from feedstock into fuel is less than the energy value of the fuel itself. It will be difficult to control demand to limit to only the level of waste available, though.
I was under the impression that modern common rail diesels, and especially the VW Pumpe Duse system, could be damaged by more than 10% BD
The BD proponents always state it's part of a vast conspiracy on the part of the engine makers not to use BD. However, it's doubtful the engine makers care if you run BD, assuming you don't damage the common rail components
If there is a failure in the common rail system while under warranty, that represents a pretty huge repair bill to the maker, like when a Prius inverter quits for no reason while under warranty
The maker doesn not want to be stuck with a huge repair bill and get into a pissing contest with a BD maker, especially if the BD maker is fly-by-night
When cars first went to unleaded gas, some motor changes had to be made, eg hardened valve seats. When "oxygenated" gasoline became pretty much mandatory in most parts of the US, and offered widely in Canada under the Husky/Mohawk brand, fuel injection components had to be changed to ensure long life
Same with BD, apparently at this point engine makers like Toyota, BMW, etc, have already done some BD tests and have had issues
VW/Audi have not approved BD in any of their diesel models that use a particulate filter to remove soot. Their statement is that BD can cause damage to the fuel system:
There is also the issue of BD being easily made at home. Which means no certification of meeting any quality standard. So a new engine might be fine with it, but the manufacturer doesn't know what type and qualityof BD may be put into the tank.
Apparently, VW and Audi have a problem with RME, which is rapeseed derived with methyl ester's. For those who do not read German, this UK site is informative
Audi UK > Owners Area > Use of biodiesel > RME biodiesel
What I found interesting is that the older non-emission Audi diesels are *not* approved for 100% RME. There must be a compatibility problem with the fuel lines, injection pump, etc
Biodiesel eats through rubber, and rubber was still being used for fuel lines up until the mid nineties by most manufacturers.
In Europe biodiesel is usually mixed with normal diesel with up to 10% being biodiesel.
Pure biodiesel is excellent diesel car killer, from old to new cars, as it lacks some lubricating properties of normal diesel fuel. That's why it is usually not sold in its pure form.
The methyl ester, right. Sounds like a similar issue that ethanol had here when first used on older carburetor vehicles
I assume the methyl ester, it is the more commonly home brewed one. Not many people try using ethanol. There's price, it needs to kept dry, and the final products don't seperate as well.
I haven't heard of BD not having necessary lubrication in it. I've heard of some research showing that you should use a different motor oil type if running 100%. BD is a stronger solvent than petro diesel, which doesn't mean it isn't lubricating.Some group IV, true synthetic oils are esters. It does make it a good fuel system cleaner. Which is good until it is put into a dirty petro burner, and accluminated dirt comes free an clogs up the filter and other parts.
As far as different motor oil, that would be true if combustion temps were much higher. Example, a conversion to run the motor on LPG/propane or on natural (Home heating) gas. The oil will experience much higher nitrification
There are oils specifically intended for use in motors running on natural gas or on LPG. These oils are formulated to resist the nitrification resulting from the difference in combustion.
From about 1975-1986 it was very popular in Canada to convert a carburetor vehicle over to propane. Entire fleets, especially taxi and school bus, were converted. Companies like Esso/Imperial Oil marketed 5W-30 and 10W-30 oils intended for use in motors running propane. Esso still has a 5W-30 oil intended for use in propane powered forklift trucks
Heavy duty engines run on propane and natural gas have different requirements. Eg they typically run a SAE 40, or 15W-40. Stationary large engines, such as those from Waukesha, run on "sour" gas also have special oils that resist the nitrification and H2S
One of the big concerns with biodiesel in the new diesel engines is that there is a post-injection cycle where fuel is supposed to vaporize to help regenerate the particulate filter. The biodiesel does not vaporize as readily as the petroleum diesel and can lead to oil dilution. Understanding the Post-Injection Problem - Biodiesel Magazine
VW allows up to B5 in the common rail TDI. One or two people on tdiclub tried running B99 in their common rail TDI. They did oil analysis somewhere around 5000 miles and were uncomfortable with the amount of fuel dilution in their oil.
Ogo, which lubrication properties is biodiesel missing? I know it has better lubricity than petroleum diesel and have seen tests that showed biodiesel has a lower HFFR wear rating.
I thought the lubrication issue had to do with nitrification of the motor oil. Is there a separate issue with common rail high pressure injection, or PD injection??
I have not heard much about biodiesel and nitration of motor oil, but oil analyses with the new engine and biodiesel still aren't that common. Right now, the results seem to point to oil dilution which was what a few publications highlighted as a potential problem. So until we know better, the feeling is that oil dilution is the #1 thing to look out for.
I don't know whether the issue is caused by the injection system or not. The North American PD's did not have a DPF so they didn't run the same post injection routine and had lower dilution levels. But PD+DPF vs CR+DPF, I'm not too sure what the differences would be.
A bit on oil and the DPF equipped PD: VW developed oil standard 507.00 for their new engines. It supposedly is intended to deal with some possibility of fuel dilution and also has lower sulfur and ash to keep the emissions system in better condition. Both the PD and CR need 507.00 when equipped with the DPF so it sounds like the oil requirements are not vastly different between the two engines. If anything, the PD may be more stringent on oil requirements.
The PD has a per cylinder plunger high pressure pump? Run off the camshaft? This is similar to the common rail used by heavy duty Cummins motors in semis. Cummins has a specific oil requirement that must be met, or rapid camshaft lobe wear will result
I wasn't aware of the fuel dilution issue in those motors. Makes sense if the regeneration phase won't work properly with biodiesel. At one time - I'm talking before 1980, certainly from the 1950's to 1970 - it was common to make a "winter blend" diesel oil by taking 20W-20, and diluting it with up to 20% kerosene
I'm sure rapid wear resulted in this practice, but for a short run it had the effect like a laxative, cleaning out the sludge and soot from the motor. Stationary diesels used at arctic DEW line radar sites had similar maintenance done to them
Yes, the PD uses unit injectors that run off the cam. The extra lobes required for the injectors required smaller lobes for the valve lifters, resulting in higher pressures at those points.
That makes sense. My experience with diesel engines is very large industrial ones, such as Waukesha, Wartsila, and old Vivian and Nordberg. These are extremely simple engines, especially the old Vivian and Nordberg motors
I'm wondering if the companies that make biodiesel, especially the rapeseed derived methyl ester, considered the impact of that fuel on fuel injection components?
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