Long-time followers of this blog may recall a Post I wrote 11 months ago about the car that I bought in 2013:
https://steemit.com/cars/@auskiwi/citroen-c5-end-of-an-era
Just recently, I have been researching into the possibility of using free waste vegetable oil as a fuel additive and supplementary fuel by adding it to the diesel fuel in the fuel tank of my Citroen C5 at a ratio of up to 10%.
You can read about the theory of how this works at this link:
https://genesisnow.com.au/Idea004.pdf
The only catch from the research I have done, is that modern common rail diesel engines, like the one I have, can't run on SVO (straight vegetable oil) as it is about 11 times more viscous than diesel fuel, so the fuel pumps can't handle it, and it doesn't atomise cleanly in the injectors.
So although I have found a source of free waste oil, which I can filter so it is clean enough to use as a fuel, I can't run my car 100% for free, all I can hope to do is reduce my running costs by diluting the diesel that I purchase for $1.49/litre, and maybe get a 5-10% discount that way. I'm also hoping that the extra lubricity of the vegetable oil will make the engine run more smoothly and thus boost the fuel economy a little.
I have only just picked up 20 litres of waste vegetable oil (also known as used cooking oil) from a local waste oil recycler who was kind enough to let me have it for free. He gets a constant supply of the stuff from restaurants and takeaway shops in the area, so much that he literally can't use it all. He filters it and resells it as cooking oil at $1.75 a litre but I don't think the market for it is there. Maybe restaurant owners prefer to cook in new cooking oil rather than used.
Anyway, I have made a home-made filter by inserting a roll of toilet paper in an empty plastic water bottle. Believe it or not, I got this idea from an actual in-line engine oil filter kit that was popular in the US a few decades ago - apparently if you use an engine oil filter that uses a toilet roll as the filter cartridge, it cleans the oil in your engine much better than the regular oil filter.
I will do a new Post with an update on how it went after I have filtered some oil and tried running the engine on a Diesel/WVO blend.
Update 01/06/2018: I filtered about 600ml of waste vegetable oil overnight, so will be starting with a 1% blend when I fill up the tank tonight. If all goes well, I will increase the percentage on the next fill...