Blending diesel/biodiesel with WVO/NewVO

[Bio Popo Member Find all posts View Profile Close Bio Popo]

Hi everybody,
I had somone tell me that you could actually just pour in new vegetable oil into a diesel tank with some diesel fuel already in there and it would perfectly fine.
So I was wondering, could you add WVO oil to diesel fuel? How about WVO to biodiesel? Or just new vegetable oil to biodiesel? Is it simply the new vegetable oil to diesel or do other combinations work?

Thanks everybody!
Dave

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Blending diesel/biodiesel with WVO/NewVO

Dave,
I have used Used Cooking Oil in blends with biodiesel for a long time. One point to remember, is that the whole amount of the blend is excisable, even if only 1% of the blend is biodiesel (or diesel, petrol or kero) Ensure that the UCO is adequately filtered before adding to your vehicle tank.

One issue with come IPs is that they are intolerant of cold UCO, The IP temperature on a CAV/Lucas/Delphi rotary IP should be measured by placing a temeperature sensor in the return line hose, to determine when to select UCO.

Other rotary IPs can be susceptable and others may have problems, so to be safe, I recommend that you add a temperature sensor to the IP return line to ensure that the IP internals are >50°C before changeover.

The installation of a fuel heat exchanger at the IP inlet will assist preheating the IP and allow more reliable and rapid changeover to UCO.]

Obviously, the fuel system must be purged to minimise starting issues.

Note: some IPs are intolerant of moderate amounts of vegoil and may refusre to start due to this issue.

[Bio Popo Member Find all posts View Profile Close Bio Popo]

Re: Blending diesel/biodiesel with WVO/NewVO

I think we may have a misunderstanding. I am not thinking about using two seperate tanks, but just combining/blending the biodiesel or diesel with vegetable oil or WVO in the same tank. I heard this could be done.

Thanks,

Dave

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

Re: Blending diesel/biodiesel with WVO/NewVO

Some have used one tank and either heated it before it goes into the injector pump to thin the oil, or just mixed it with diesel, kero, heating oil or even petrol to thin the oil.
I think the question is not if can you do this, but if you do, How long will the engine last, cold vegetable oil is to not likely to spray properly in the engine, causing it to form greater amounts of carbon. If it has any water in it this is likely to corrode the injector pump. if it is acidic it can attack other parts. If you have an old bomb of a car give it a shot, if an immaculate low kilometer car, I would think twice.
Pity really, it would be heaps easier.

Chris.

[Tony From West Oz Vice Chairperson of WARFA Find all posts View Profile Close Tony From West Oz]

Re: Blending diesel/biodiesel with WVO/NewVO

My apologies, I got off topic there didn't I.

Bearing in mind that some IPs are not suitable for using even low % blends (see earlier post) of vegetable oil, It is possible to operate many IPs with low % blends (<20% Vegetable Oil). Some IPs may operate reliably with high % blends (25 - 75%) and some are OK with 100% vegetable oil.

The issues of engine longevity due to carbon build up, ring coking, oil dilution and polymerisation will need to be considered.

I am experimenting with a 50% blend in a Mercedes 300D, using a small heat exchanger to assist by raising the fuel temperature. The OM617 engine is one of the few which I believe can operate reliably on a high % blend of unheated vegetable oil without having serious consequences. That said, I have had a report of one of these engines suffering from excessive carbon build up in the combustion chamber, while using a high % blend.

If you are planning on experimenting with the use of blended vegetable oil fuels, I recommend that you incorporate a few of these suggestions to allow you to monitor the engine condition during the tests.
1. Baseline the engine - have IP overhauled, - Have Injectors cleaned and set, - Have the cylinder compression pressures tested, - Have the engine oil analysed for wear metals, soot and (if possible) for oxidised triglycerides.
2. At every service have the oil analysis repeated.
3. At every alternate service (or annually), have the compression tested, have the injectors inspected and if necessary cleaned and tested/reset.

If you are using blended vegetable oil fuels, the addition of a coolant/fuel heat exchanger prior to the injector pump would be advisable.