PowerSwitch

Back in May I discovered that a company based just over the road from where I work has designed a system to convert any diesel fuelled vehicle so that it can also burn vegetable oil (fresh or used). After a delay of a few months (for various reasons) my car has now had the conversion done. In this thread I'll describe why I've had this conversion done, what it involved and how the car's running. Hopefully I'll get some pictures in here as well.

Before I start, I'd just like to quickly summarise my views on biofuels. I don't believe we can all continue to travel the way we do on biofuels instead of oil, as the land area required to provide the fuel would simply be too great, aside from issues of fossil fuel inputs to the farming process. However, biofuels could allow essential transport systems (emergency services, public transport, tractors, etc.) to continue to operate when oil is in short supply. I hope that by people like me converting vehicles to run on biofuels now, before it is essential, it will be possible to develop the technology and infrastructure that we will need when there is less oil available.

In the long run, I intend that my wife and I will go down from two cars to one, and then to zero, but this will take time as we will need to change jobs and maybe relocate. Until this happens, I'm hoping that by running my car on a biofuel I can reduce my impact on fossil fuel use and CO2 emissions, especially as I'm burning used veg oil which would otherwise be going to landfill or incineration. (Some used oil does find it's way into biodiesel production, but with the current tax levels on biofuels, this isn't really commercially viable). I'm also finding that it makes people sit up and think - they can see I'm serious about Peak Oil and that I'm spending my own hard-earned cash in preparing for it. There's also the added advantage that as long as we're living in a situation where it's difficult to manage without a car I'll have a more secure fuel supply, as I can safely store vegetable oil at home. Hopefully this will enable me to make any essential journeys in a time of shortage, and also help out friends and family.

OK, that's the intro over, here's the technical details:

My car
VW Polo 1.4 TDi, 2001 Y-reg
Usual fuel consumption on a variety of roads: 65mpg if I drive gently, 55mpg if I drive fast

The Conversion System fitted
Smartveg, an 'intelligent' semi-automatic system produced by Regenatec. http://www.smartveg.com/

What's been added for the conversion to veg oil

• Extra fuel tank (33l) - this is in the boot, and is full of veg oil, the main tank still holding diesel.
  Heat Exchanger - this uses the engine coolant to heat the incoming fuel.
  Filter heater - this uses the engine coolant to heat the fuel filter, essential if you want to burn used veg oil, which contains heavier oils.
  Fuel valves & temperature sensor - these monitor the fuel temperature and switch fuel supplies.
  Control module - electronics to monitor temperature and switch state, control the valves and display.
  In-car switch & display - switch to select fuel supply and display to show system status.

Overview of the system operation
Initially the engine is cold, and the fuel system is filled with diesel. After the engine is started, and it warms the control module senses the fuel temperature and begins to mix a progressively larger proportion of veg oil into the diesel supply, until after a few minutes there is no diesel being used at all. The exact length of time to warm up depends on the ambient temperature and the design of the engine. When you are almost at the end of your journey, you instruct the system to "flush", which takes about a minute. This flushes out the veg oil from the engine's fuel system using diesel, so that when you restart the next day with a cold engine, there is no veg oil present. Of course, if you know you will only be stopping the engine for a short period, you can leave it on veg oil, as it will still be warm when you restart.

Detail on fuel and temperatures
Veg oil is thicker than diesel, and as the engine was designed to run on diesel, the veg oil needs to be heated in order to have roughly the same visocosity of diesel. Putting cold veg oil into the engine could result in poor operation and even internal damage, as oil droplets may land on the metal surfaces inside the engine and turn into a kind of "lacquer" which will wear the piston rings. This is the clever bit of the Smartveg system - it monitors the temperature of the fuel, and as it warms up it starts to mix in veg oil with the diesel in increasing proportions until the engine is fully running on veg oil. In this way, the possibility of damaging the engine in massively reduced. The Smartveg system heats the fuel by passing it through a heat exchanger, which has engine coolant flowing through it.

Why the heated fuel filter?
If you want to run on fresh veg oil, a normal fuel filter is fine. However, if you want to run on used veg oil, you need to heat the fuel filter, especially in winter. This is because the oil has been used in cooking, and although it has been filtered there are still traces of heavier animal fats dissolved in the oil. When the oil is cold, these can come out of solution, and clog up the filter. By heating the filter, it ensures that the used oil will pass through it without problems.

What the in-car display and controls do
The only control in the car is a simple switch - up for diesel and down for veg oil. You can put the switch down when you start the engine, and the system will then automatically switch to run on veg oil as soon as the fuel has warmed up sufficiently. At the end of the journey, flicking the switch up again will start the "flush" procedure. The switch has a status LED, which is off for diesel, on for veg, and flashing during flush. There is also a buzzer to tell you when the system is changing from diesel to veg, when it has completed the flush, and to warn you if you turn off the ignition without flushing (this warning can be ignored if you know you are only stopping for a short period).

In addition to the switch, I've also gone for the optional display unit. This performs several functions:

• - When the engine is cold, it shows a warm-up progress bar, at the end of which the switch to veg oil can start.
  - When the engine is warmed up, it shows the fuel level in the veg oil tank (the fuel level sensor and suitable tank are also optional upgrades)
  - During a flush, it shows a progress bar, at the end of which you can stop the engine

Conclusion
Well, it works, what more is there to say?! I've had it in there for a week now, and have driven 200 miles or so. I'll update this thread with further information on fuel consumption, performance, and answers to any questions. Oh, and photos too when I get round to it.

A very detailed and informative post, nice one!

Where do you get your fuel from?

Do you "fill up" in a way similar to with regular fuel?

When you talk about "home storage" I'm think a huge 6ft square block of solid cold fat or a big tank with in-built heater, plumbing and fill-up nozzle, what's the real story?

If you could source your own raw waste veg oil could you "process" it yourself and just whack in the tank and not pay any tax? (hypothetically, of course)

Do you get the same MPG on veg oil as you get on regular diesel?

What about emmissions? Does the veg give the same level of emmisions? I bet you'll be turning the veg system OFF when you go for an MOT.....

Kudos for taking the plunge.

fishertrop wrote:A very detailed and informative post, nice one!
Kudos for taking the plunge.

Cheers

fishertrop wrote:Where do you get your fuel from?

I'm buying it from the place that fitted the system. They get it from a wholesale place that has collected it from restaurants, etc. and filtered it so it is safe to use as fuel. It's currently 70.4p/litre.

fishertrop wrote:Do you "fill up" in a way similar to with regular fuel?

Not quite. Diesel still goes into the main tank as normal. The veg oil tank is in the boot and filled through a cap - I've bought a large funnel! However, the place selling the fuel is installing a pump shortly. It is also possible to get a second filler cap cut into the vehicle, but that was more than I wanted to do for now - at the moment the car could be returned to normal and the kit put on another vehicle.

fishertrop wrote:When you talk about "home storage" I'm think a huge 6ft square block of solid cold fat or a big tank with in-built heater, plumbing and fill-up nozzle, what's the real story?

Nothing so grand I'm afraid - at the moment I have a couple of 20-litre water carriers that I got for ?5 each. I should be getting hold of some old 20l wholesale oil containers to use as well. I plan on storing about 100 litres, mainly so I can just call in once a month to fill up. They have some people turn up with 1000 litre fuel bowsers and fill them!

fishertrop wrote:If you could source your own raw waste veg oil could you "process" it yourself and just whack in the tank and not pay any tax? (hypothetically, of course)

Yes, you could. You need to filter it, and I think you should heat it for a time to separate out any traces of water. Not sure on the exact process. It is possible to do this in a legal way - you have to register with customs as a "fuel producer" and then pay them 27.1p per litre that you "produce" - that's a 20p discount over diesel/petrol. Registration is free, it's just a bit of paperwork and maybe an "inspection". I'm sticking with my supplier, as I get a receipt for the duty. Of course some people might be tempted to just buy fresh oil at the supermarket at ~43p/litre and tip it in, no filtering required, but that would be illegal...

fishertrop wrote:Do you get the same MPG on veg oil as you get on regular diesel?

Don't know yet, but I should do. Apparently it's normally +/- 3% performance (and efficiency), depending on the quality of the oil you happen to have.

fishertrop wrote:What about emmissions? Does the veg give the same level of emmisions? I bet you'll be turning the veg system OFF when you go for an MOT.....

Well, there's no sulphur in it, so no S02 in the exhaust, which is good. Particulates have been reported to be slightly lower. Other pollutants should be about the same. When I go for the MOT, will probably run on diesel, but I'll ask them to test the veg too, just out of interest.

Update on my veg oil system and flushing time

The SmartVeg system flushes out the veg oil at the end of a journey by pumping diesel into the fuel system and opening a valve to return unused fuel direct to the veg oil tank. This is done for 60 seconds, followed by 30 seconds normal operation, after which you can stop the engine.

However, the only actual requirement for the flush is that all the veg oil is gone from the engine. The people who installed my system did a test a couple of days ago, and found that for my particular car the veg oil is all flushed out in about 20 seconds, and after 60 seconds it has flushed something like 1 litre of veg oil and diesel back into the veg oil tank. While this isn't a problem, it does mean that more diesel is getting burned than need be.

So, my car is with them again today for a few minutes for a firmware update (firmware is software embedded into the control module). This will adjust the flush to 30 seconds of returning fuel to the tank (so as to leave a margin for error), followed by 30 seconds of normal operation. Hopefully this will reduce my diesel consumption to not much over half a litre per trip starting from cold. This is important, as for shorter journeys there is obviously no point in switching to veg oil if you are going to end up flushing more diesel back into the veg oil tank than the amount of oil you burned.

Surely an electric pump/heater would be more to the point? Imagine what would happen if you ran out of diesel? Can you flush the system by hand?

Bandidoz wrote:Surely an electric pump/heater would be more to the point? Imagine what would happen if you ran out of diesel? Can you flush the system by hand?

It's true that it would be nice to have fuel heated electrically before it went into the engine, but that still wouldn't deal with the fuel physically inside the engine at ambient temperature, so you still end up having to flush the fuel system out with diesel if you're stopping for long enough for the engine to cool down. Some people use an in-tank heater, but that's only to stop the fuel filter clogging I think, and my filter heater acheives the same result without consuming any extra electricity, as it uses engine coolant as the heat source.

Running out of diesel would be a problem, but should not happen easily given that I'm only burning 1/2 litre per trip and I have a couple of jerry cans of diesel in my garage in case of emergencies. If, for some reason, I did run out of diesel (or veg oil for that matter), then once I had put some in, the SmartVeg system has a special "purge" mode which can be used to very quickly flush everything out of the fuel system with either veg oil or diesel.

What is really a shame is that engines are designed such that they only work on mineral diesel, unless you add a kit like this. The original diesel engine ran on peanut oil, and if modern engines had slightly different pumps, injectors and fuel lines they could run on veg oil only too.

I seem to remember K&N make a water heater that brings the engine up to temperature more quickly - perhaps it may be of some use?

Yes, heating the engine up faster might help reduce diesel consumption. As it is though, I'm switching to veg oil after not much more than half a mile. It will be different in the winter of course.

One of the neat things with the VW Tdi PD engines is that the cam-driven injector pumps get the fuel very hot, so for my engine the fuel could well reach a suitable temperature for veg well before the rest of the system is warm. This works because the fuel is going through a recirculation loop, including the engine, injectors and low-pressure pump, so the fuel gets progressively hotter as it cycles round, with only a few precent of it being fresh fuel drawn in as some is burned.

More info on the issue of electrical heating of veg oil for a diesel engine, direct from the people who installed my kit:

An electric heater can only be employed to generate around 150 - 200
Watts. Beyond this and the loading of your alternator becomes
excessive. Even at 200W current draw is over 14 Amps - and that power
(plus losses) has to come from increased fuel consumption. More
importantly, from our extensive work with thermal imaging, we found that
200W just isn't suffucient to warm the IP. Heat is sucked away from the
pump in to the cold mass of the engine block. Only by supplying heat
via coolant (well in excess of 200W) and allowing the engine block and
pump to attain some degree of thermal stability can veg oil be
introduced safely into the pump.

There will be some more info on this issue on their website in the near future: http://www.smartveg.com/

The Guardian is covering alternative fuels, including veg oil:

http://www.guardian.co.uk/oil/story/0,1 ... 90,00.html

Further to the talk about coolant heating versus electrical heating, here's an infra-red image of a car (not mine) with the SmartVeg system fitted, with the hot fuel pump labelled. As you can see, the fuel pump is around 60-70C, which takes a lot of heat input - more than you'd want to do electrically. The temperature of the fuel pump is critical, as if it is too cold the veg oil will be too thick and it might break.

I saw diesel for sale at 99.9p/litre over the weekend. I'm certainly glad I'm running on veg oil at 70.4p now!! It'll pay for itself in no time if the prices keep rising...

Here are the pictures, at last:

First, here's the 33-litre tank in the boot of the car.


And here's the controls inside the car. Note the switch on the left to select between diesel and veg, and the multi-function display on the right:


Here's an overall view of the engine bay:


Here's the new fuel filter to handle the diesel, and the bulb pump which is used to prime the veg oil line after installation, and also if you happen to run out of fuel.


Here's the heat exchanger. Note the small pipe carrying fuel coming in at the right hand end, and the coolant coming in through the bigger pipe from the top on the left hand side. In total the heat exchanger is about 1.5 metres long, so we're only seeing one end of it here:


Here's the original fuel filter, which now has veg oil going through it. Note the copper coil using engine coolant to heat the filter to stop it clogging up when running on used oil in the winter:

And finally, here's the valves to control the fuel supply - you can see one of them, the other is round the back of the metal plate they are mounted on. The white cable at the bottom of the picture heads off through the bulkhead to the control electronics.

OK, some big news here!

The company which fitted the veg oil conversion to my car is going to be filmed tomorrow afternoon by the BBC for the Wednesday edition of "Working Lunch". They are focusing on the lorry conversions that they do, in the light of the fuel protests, but they also want to film a private car conversion - mine!

Better still, they want to know why I got the car converted, given that it will take a few years to pay for itself (compared to months for a lorry). At that point, my answer will obviously be Peak Oil!

Now I don't want to get too excited yet, as I know what these things are like - they may run out of time and not film me, whatever I say may get cut in the final release, etc. but I'm really hoping that this will be a good chance to get a bit of peak oil publicity into the mainstream media.

Wish me luck!

mikepepler wrote: Wish me luck!

Good luck Mike.

Mentally rehearse what you want to say beforehand, do some deep breathing and (try to!) keep calm. Being interviewed with a camera pointing at you can be quite nervewracking if you haven't done it before.
Try to speak slowly and clearly, as the tendency can be to break out into a fast nervous gabble...

If you do. your bit will stay in the trim bin and not make it into the edit!