Common rail diesel injection

[gtemco Biofuels Forum Newbie Find all posts View Profile Close gtemco]

Hi - I am a newbie to the forum. Has anybody out there been using BD100 in a new generation high pressure common rail diesel engine, as used by most diesel vehicles from 2005 on? e.g. Peugeot HDi, Mercedes CDi, New Ford Transit Duratorque, Renault DCi etc.

As you would expect, the makers of these engines say that biodiesel should not be used and will void any warranty but they are not specific as to what damage, if any, could be caused.

I have been running my old 1999 Ford Transit 2.5Di on BD100 for 40,000 miles with no problems other than I had to have the seals in the pump replaced with Viton seals. At some stage I will have to replace the vehicle with a brand new model; hence my question.

[Robert Administrator Find all posts View Profile Close Robert]

Re: Common rail diesel injection

Hi gtemco,

Someone was only asking a couple of days ago about using biodiesel in a Ford Transit van...

As for common rail, there is something in the warning about the use of bio in a common rail engine, but not what the manufacturers would have you believe. In a common rail, fuel can be exposed to higher temperatures and more recirculation than otherwise. The fuel that is in the rail gets up to 100°C and most of this does not get injected, but recirculated back to the tank, where it has the chance to be exposed to air again. This increases the chance that it might oxidise.
Now, biodiesel that meets spec will have a very high oxidation stability, meaning that it takes a long time before it can go bad. In a common rail system, the speed that oxidation can happen is increased, or the time at which it can resist is decreased. This is not a concern if your biodiesel meets spec, but if not, then it could be an issue.
This does not seem to prevent manufacturers telling you that biodiesel is not suitable because of common rail. Fortunately, you are better informed than just to blank it out.

There has been some discussion in the forums here on this recently. Have a search, or look at this thread where this is also discussed.

[gtemco Biofuels Forum Newbie Find all posts View Profile Close gtemco]

Re: Common rail diesel injection

Thank you Robert. The possibility of accelerated oxidation of biodiesel in common rail systems hasn't been explained to me before and I therefore find your posting extremely informative. Other reasons that have been put to me to not use bio in common rail engines, mainly relate to the onboard computer systems that these engines use, i.e. bio may upset the various sensors that these systems use and cause the computer to shut the engine down to 'limp mode'. As a home brewer of BD I don't have the means to ensure that every batch I make meets the ISO or EN spec. I titrate accurately and my finished product looks good, feels good and runs well in my present vehicle......but do I have the nerve to use it in a brand new £20,000 CDi or DCi common rail vehicle? Not yet. I guess I am waiting for some other home brewer, far braver than me, to take the risk and report the results. Of course I could try commercially produced BD that is guaranteed to meet spec, but in the UK commercially produced BD is no cheaper than petro diesel, because our government still want their tax cut, unlike some other European countries where BD is duty free. Regards - Ian

[Robert Administrator Find all posts View Profile Close Robert]

Re: Common rail diesel injection

Hi Ian,

Tax is the same issue here in Australia, but most of us are not using biodiesel purely for the economic benefits.
Not sure re the sensors, I think that may be a red herring, as the sensors do not sense any chemical properties of the fuel, they will sense flow speed, temp, etc, so I'd guess this sounds like the sort of thing that "expert" service people come up with to justify a position that they think they should have on biodiesel without ever having done any real tests on it themselves. I do know that the old Freelander L-Series model used a sensor on the first injector that was contained rubber component that swelled with biodiesel (i.e. not Viton) and this caused that sensor to malfunction. I'd doubt that modern engines would employ such materials any more.

If you wanted some confidence about the oxidation stability of your home brew, you could possibly build your own rancimat tester. A rancimat is a very expensive machine that test labs complain about having to buy for biodiesel testing. It accelerates the oxidation of the fuel by heating it and bubbling air through it. During this process, acids are formed which will drip into distilled water. Testing electrical conductivity in the water will tell you when a certain degree of acidity has been reached. I've often thought that a person with enough of an interest in this could probably build their own home made rancimat with aquarium heaters, air pumps, some simple chemical brewing apparatus and a multimeter. If anyone ever does (or ever has), I'd be keen to know about it.

[Matt Senior Member Find all posts View Profile Close Matt]

Re: Common rail diesel injection

With regard to all this may I add that my 2004 Peugeot 307 HDi has not yet complained about my homemade biodiesel, 39,000 km and counting. I have not had any tests done apart from my obsesiveness. Run on it since new, almost, the initial tank was mineral diesel.

Please do not mention the sensor thing as my car has not yet figured that one out. In my mind if the sensors play up then they have been made of inferior materials anyway, what consolation that is, is debatable though.
Matt

[gtemco Biofuels Forum Newbie Find all posts View Profile Close gtemco]

Re: Common rail diesel injection

Hi Matt - Very interesting; your input has boosted my confidence in using 100% bio in my new common rail diesel when I get round to buying it. Anybody else out there who has been using 100% Bio in a common rail diesel or VW PD diesel, then I'd love to hear from you. Thanks - Ian

[ilan Biofuels Forum Newbie Find all posts View Profile Close ilan]

Re: Common rail diesel injection

hi Ian- I have exactly the same dilemma. I drive a 98 toyota hilux on 100% biodiesel without any problem and am considering changing it for a newer model that has a common rail injection system.
I would like to know if there is problem using b100 with a common rail , will it be felt immeidiatly from the first tank.

[Matt Senior Member Find all posts View Profile Close Matt]

Re: Common rail diesel injection

Guys, I have read about the possibility of polymerisation and oxidisation in the high pressure and consequent high temperature environment in the injection rail and engine area.

Firstly I do not believe that temperatures will exceed a normal engine compartment by a great deal and polymerisation is a fuel quality factor so with good fuel I do not think this is an issue. After 41,000km I have not detected any injection issues, its running the same as it was when new. As for the oxidisation factors with out the presence of oxygen in the common rail system it simply will not oxidise or breakdown. How it behaves in such a high pressure environment is the major issue I cannot quantify. If Peugeot are saying 30% bio is fine then it must not be too much of an issue as I sincerely doubt mineral diesel will be any form of solvent or cleaner.

I ran on it since new and do not as yet regret one moment (well maybe one when I was filling by hand and did not register when the tank was full.)

Matt

[moonan Member Find all posts View Profile Close moonan]

Re: Common rail diesel injection

My R5 TDI VW engine (PD) has now 70,000km on an average of about B20. When I have had the opportunity, it has been up to B100. No issues apart from the expected "power slightly down, fuel use slightly up" described in the VW manual.

Neil

[Captain Echidna Senior Member Find all posts View Profile Close Captain Echidna]

Re: Common rail diesel injection

up" described in the VW manual.

I heard some WV manuals say biodiesel is the prefered fuel for the car. Wha does yours say? How much does it say is OK?

[moonan Member Find all posts View Profile Close moonan]

Re: Common rail diesel injection

My V-dub is in the shop having the water pump replaced (4 days, they have to drop out the transmission to do it!) so I can't quote the manual, but it speaks generally about RME (rapeseed metyl ester) or generally FAME (fatty-acid methyl ester) being suitable but not for models with diesel particle filter, as long as it meets the euro-spec. Penalty for bad-spec fuel is listed as blocking fuel filter. Increased maintenance is listed as changing fuel filter @ 30k instead of 60k, and the warning about performance and fuel use I quoted earlier..

[Robert Administrator Find all posts View Profile Close Robert]

Re: Common rail diesel injection

Hi Neil,

The DPF (particulate Filter) is another one of those latest "you can't use biodiesel because of" things. As with the common rail, those who say such things are not totally without reason, but the real reason is:

The DPF gets clogged up eventually and needs to be cleared. This is generally done by heating the filter beyond what it is used to and burning all the soot that has clogged it. To heat it, extra fuel is injected into the engine, resulting in a higher exhaust temperature and doing the job nicely, with a small penalty to fuel economy. However, the exhaust temperature with biodiesel can be up to 100° lower, so the ability to purge the filter by burning off the soot is diminished.

In itself, that seems like a sensible reason to say "not suitable for biodiesel". If you look a little further, biodiesel also has significantly less particles to clog the filter. There have been many European tests done on this which show biodiesel extending the life of the DPF for this reason, yet none of those tests have been done by the manufacturers who simply say "don't use it".

It is true that using biodiesel in a car with a DPF will limit the ability for the filter to self-purge. However, an intelligent person would know that it will get less clogged to start with. Lastly, if it wants a purge, why not put a tank of dirty dino diesel in to let it have its extra heat one in a hundred tankfuls if it needs it.

I know I'm off topic, but I couldn't resist.

[JP1 Biofuels Forum Newbie Find all posts View Profile Close JP1]

Re: Common rail diesel injection

I am also new to this discussion. I have an 07 Jeep Grand Cherokee with a 3.0 L Mercedes CRD. Diamler Chrysler claims that 100% would void the warranty. Frankly with the cost of diesel it seems to be worth the risk. Does anyone else on this panel have either a Jeep or Mercedes to compare?

[magconpres Biofuels Forum Newbie Find all posts View Profile Close magconpres]

Re: Common rail diesel injection

I am also new to this discussion. I have an 07 Jeep Grand Cherokee with a 3.0 L Mercedes CRD. Diamler Chrysler claims that 100% would void the warranty. Frankly with the cost of diesel it seems to be worth the risk. Does anyone else on this panel have either a Jeep or Mercedes to compare?

I have an 08 Jeep with the Mercedes CRD. I haven't run Bio myself in it beyond B5 yet, but have read posts from others who have.

Those posts were on either Jeep Forum - Jeep Enthusiast Network or BioDieselNow - Renewable biodiesel fuel

One person has over 10k miles on his with varying BD % from B20 to B99.

There is an online BD magazine with an article on the impact of BD on engine oil life. I am having my oil analyzed every 1000 miles to establish a baseline and will then start increasing my use of BD.

There is also an article somewhere on the net discussing polymerization of BD on engine parts. It is from Africa and the sutyd concluded that an AC Delco additive was effective in inhibiting this effect.

I'll be adding a fuel heater and aux filter before my IP to make sure the viscosity is low enough to not strain the pump.

I'll post more info when I have it.

[mr.damage Junior Member Find all posts View Profile Close mr.damage]

Re: Common rail diesel injection

Hi Matt - Very interesting; your input has boosted my confidence in using 100% bio in my new common rail diesel when I get round to buying it. Anybody else out there who has been using 100% Bio in a common rail diesel or VW PD diesel, then I'd love to hear from you. Thanks - Ian

Hi gtemco
I have been using b100 in my PD VW Polo for over 60,000 km only ran fossil diesel for first 7500 km of its life and on a trip to Tasmania where I could not get any bio. When I came back from Tassie I had no end of problems because some of the fossil diesel I got had algae in it. Cleaned it out and it is all good again.