I thought it was worth starting a thread to try and summarise what different people have tried, and in what engines. There's a load of information out there on the web, often conflicting. For example: some people on the TDI Forums will tell you not to run Veg Oil as it will wreck your injectors and engine. Others are doing it daily and swear by it. With the price of fuel soaring ever higher, any legal method of saving money on pump diesel is going to be tempting. At the time of writing this, pump diesel is around 1.40 per litre. Just so we're clear from the start: Opinions and information on this thread carry no warranty whatsoever. Use them entirely at your own risk!! Alternative fuels will almost certainly invalidate any manufacturer's warranty. So, what people seem to be trying, from scouring round forums. Bio Diesel - becoming more widely available from specialised filling stations. New Vegetable Oil (SVO) - either 100% or mixed with pump diesel / Petrol / other additives Waste Veg Oil or mixes Things to think about: - Any extra maintenance needed? e.g. fuel filter changes - Summer vs Winter conditions - Long term impact on your engine - e.g. injector blocking / fuel pump rebuilds / piston ring sticking.
Brookster's Twin Tank Setup in his transporter, running filtered waste veg oil. http://www.clubgti.com/forum/showthread.php?t=220979
Bio Diesel. A mate of mine was making his own for a while. He's now stopped as it was a lot of hassle, he's bought a corrado 16v, and the bio tank setup took up most of his garage. http://thebiodieselcook.blogspot.com/ Bio Diesel Filling Stations, and info on which cars can run on it. http://www.biodieselfillingstations.co.uk/outlets.htm
Mike Diesel LPG Conversion 80/20 mix Basic LPG Diesel Kit I'm also fitting an LPG Kit to the Transoprter to run 80% SVO & 20% LPG This will give me a cleener burn at present the IDI Engine only burns 80% of the Fuel Injected but with the LPG Injection it will give a 100% giving more power and more MPG. Plus Cheaper Fuel http://www.tinleytech.co.uk/lpgprices.html Diesel LPG Conversions Diesel engines can be converted to run partly on LPG, partly on diesel. This method uses the combustion of the diesel to ignite the LPG. The benefits include large increases in power and reduction in emissions, particularly the black smoke often associated with diesels. Typically a ratio of 30% LPG to 70% diesel is possible. No adjustments are required to the diesel injection system and fuel savings come from the fact that throttle openings are lower due to the greatly increased power, which basically means you do not have to press the accelerator as hard to get the same performance. Fuel savings up to 30% are possible with the increased power levels seen as a major benefit to users. My conversion will be for Additional Fuelling instead of an LDA on the injection pump i have now decided to go for my first plan on the additional fuelling under boost LPG T: I've sourced the parts required and basically i will have a LPG Vapourisor adding the Fuel controlled by an Adjustable Pressure switch. so when i get upto 0.3bar the LPG will kit in and add 10% LPG this will also give me a 100% burn of the Veg Oil / Diesel and lower emissions and EGT's. The Current IDI Engine design only burns 80% of Fuel injected so the LPG Enures a more efficient burn some info here - http://www.mrsharkey.com/lpg.htm How it works:Introducing LPG gas into the combustion air intake of a diesel engine acts as an accelerant, promoting the even burning of the diesel fuel, and more complete combustion, resulting in more power being produced. Many web pages and forum posts will call LPG a "catalyst" but this is not correct, as LPG creates no change in the molecular makeup of either the air or the diesel fuel. Propane by itself resists self-ignition inside a diesel-fuel compression-ignition engine due to it's high flash point and narrow fuel-to-air ratio. During the compression stroke, the air/LPG mixture is compressed and the temperature is raised to about 400C, not enough to ignite the LPG, which has an ignition temperature of about 500C. In the small concentrations that LPG fumigation uses, the LPG mixture is not rich enough to be overly flammable and is more difficult to ignite. When the diesel fuel is atomized into the cylinder under high pressure, it immediately self-ignites (diesel ignites at about 385C.), and causes the LPG to burn as well. Since the LPG is in mixture with the air, the flame front from the diesel spreads more quickly, and more completely, including igniting the air/fuel mixture which is in contact with the cylinder walls, which are cool in comparison to the super-heated air inside the combustion chamber. Much of the cleaner burning of the fuel is attributed to this ignition against the "cooler" components of the engine, and accounts for raising the percentage of combustion from a typical 75% for a well-tuned diesel engine running on pure diesel fuel alone, to 85-90% with the addition of LPG. Obviously, this more complete combustion also gives a nice boost in power, with an accompanying increase in fuel economy and reduction of pollutants. Turbocharged diesel engines are able to realize a significant increase in power by using LPG fumigation. While the usual suggested increase is considered to be approximately 20%, by careful management of the gas introduction, power gains of up to 40% are possible
So you'll have a triple-tank setup? As I'm running an Audi 80 Avant, I don't want to put an extra tank inside the passenger compartment. For me, any sort of multi-tank setup isn't an option. I'm seriously considering running a mix of veg oil and diesel though, which hopefully would get some of the benefit without the time and investment needed to set up a different fuel system. What are the changes needed (if any) and risks of running... for example... 50:50 veg oil: diesel. Would that work in winter, or should there be more diesel in the mix. Is a heat exchanger needed for a setup like that, or will the mix of diesel and veg keep it liquid at winter temps? Does new veg oil block up the fuel filter? What sorts of veg oil can be used? Anything at all (sunflower, corn, rapeseed) or is it better to stick to specific types?
I'm on single Tank Set up now since having the injection pump built to Veg Oil Spec,and the LPG Tank will also be used for running the Fridge and stove in the T4 which works out cheaper than buying Calor Gas and also the tank is under the Van Rebuilt Bosch VE Injection Pump If you run 50/50 mix you can just have single tank but i would use a heat exchange to takeany strain of the injection pump in the cold weather I would fit a heat exchanger for any Veg Oil Use My Heat Exchanger (Right hand side of Expansion Tank) New Veg Oil will not need the regualor filter change like WVO does, the only thing you will have to do is change the filter after using your first tank as it will pull any dirt out of your existing tank due to its sticky nature, after the first tank you will be fine. I've been running the same fuel filter for 8 months now Rapeseed is the best and i have used Soya but it has a stronger smell so i only use it if i can't get Rapeseed
Does the cost in the saving of diesel with a supplementary lpg system not get countered by the cost of the lpg?
LPG is only about half the price of diesel per litre, IIRC. So cheaper than new veg oil, but more than waste veg oil, if you're filtering yourself. About the same as pre-processed, at some of the prices quoted. The LPG idea looks interesting. I'm not clear from the kit costs how it's mapped for the individual vehicle. any ideas on how thats done. With the number of different diesel setups out there (mechanical, ECU controlled DBW, IDI, TDI, NA, etc) then how do you make sure the kit is compatible? From reading this link above on Brookster's post http://www.mrsharkey.com/lpg.htm it looks like it's governed by the airflow into the engine. Makes sense I guess.
The last lpg kit I helped install had an ecu that learnt what the oem ecu was doing and worked out its own calibrations, however, that was for a petrol car running 100% lpg. I like the sound of lpg too though
The Open loop LPG System has not ECU or Electronic control is basically works on Vacum from the Inlet manifold which controls a diaphram in the vapouriser I have a Boost prerssure control switch that will switch the LPG on when i hit 0.3bar The kit i got cost me 80 which was a brand new small power Vapouriser 30 which is only low BHP (50max ) and a second hand Turoidal Tank for 55 (It had 50 worth of LPG in it too ) EGT Gauge essential bit of kit for Tuning the Diesel Engine i will probably fit wideband to get the mixture right but only temporary and remove once its tuned. LPG is 70p per Litre at the moment near me.
Ah I see, so basicaly as with diesel afr, lpg in a diesel is either injected in too small a quantity and makes no real difference, or too much and is just wasted. So getting the near perfect mix is a matter of econemy and power rather than flooding or melting a piston.
So fitting say a 40ltr lank of lpg, how long would that last??? and would it create enough savings in diesel to warrant the additional cost of buying the lpg? 1.40 per litre of diesel, and 69p per litre of lpg, you would need to be making a 69p saving in diesel to be able to afford the lpg. Unless for every litre of diesel you are using say 1/4 of a litre of lpg, in which case there is a saving. Dont get me wrong, im not causing a stir or piking holes, im just trying to work out if there is a true saving to be made Id love to know what the derv/lpg ratio is.
14.5 AFR and keep EGT's below 700deg C You will notice a drop in EGT's too when using LPG , the 50litre tank i have @ 20% LPG will last ages (arround 2500miles) but i will also be running my Fridge & Barbecue on it if i didn't have a camper van i would just use a small Calor Gas Bottle for the LPG injection with a 36mbar regulator and a Nitrous Solenoid with a 1.5MM JET to the LPG Injection which would give 25000BTU of Fuel Cheap DIY LPG injection set up http://www.mrsharkey.com/lpg.htm
Ah, I see what you're getting at now... I'm assuming it's more or less substitutional, and the savings in diesel from using a lower throttle opening will cover it. Brooky. Is 14.5:1 the right AFR for a normal diesel too? OK to use a regular AFR meter like an innovate LM-1? The cat has mysteriously vanished, so I should be ok to measure at the end of the exhaust pipe.
Have you got an EGT Gauge , that's as important as AFR and only 25 The diesel engine can operate at 12:1 to 24:1 at idle. The Higher the AFR the lower the EGT's (Opposite to Petrol Engines) But you need Fuel to get the Boost , so with a Bigger Turbo its easier to get the Boost and Lower the EGT's The reason i fitted a bigger Turbo on mine than a standard T4 Transporter With a diesel fuel oil consisting of 86.5% C, 13.2% H, 0.3% S and 0%O 86.5/12=7.21 where 12 is the molecular weight of carbon. So ignoring the 0.3% sulphur, we can pretend your hydrocarbon is C7.21H13.2. (I'm not saying the molecules are that short, I'm just thinking about the carbon hydrogen ratio.) CxHy + a(O2+0.79/0.21N2) => xCO2 + y/2H2O + a*0.79/0.21N2 where a=x+y/4 in this case, a= 7.21 + 13.2/4 = 10.51 AFR = a(MWO2+0.79/0.21*MWN2)/MWfuel AFR = 10.51 (32 + 28*0.79/0.21) / (86.5+13.2) = 10.51 * 137.33 / 99.7 = 14.42 14.55 Kg air to Kg fuel So a rough calculation for your fuel (ignoring the sulpher in the fuel, argon in the air, etc) gives 14.42 which is pretty close to the figure you gave - not that I ever doubted you, ..., more a question of trying to understand why things are the way they are. So why the difference to the earlier estimate? If hydrogens were about 2:1 with the carbons, we could expect an AFR a bit below 15 as indicated earlier. 7.21*2= 14.42. The actual percentage hydrogen you give is 13.2, ie less that 2 hydrogens per carbon.
Cooking oil fuelled Van (+driver) request for Wolfsburg Marathon film Some more great stuff in this thread guys. I'm now putting the feelers out to see if a Club member running a veg oil fuelled VAG car/van would be able to volunteer as camera car/driver for my STROKE charity trip to Wolfsburg in May. Fuel and travel accommodation is covered. It's my idea to free up the film crew to give them more filming options and also to carry on the veg oil theme. It also gives a fellow VeeDubber the chance to visit Wolfsburg/Autostadt :-) anyone interested? The dates you'll have to take off work and family are 19th to 29th May