Volvox Fuels, Supplies and Systems

They are all constructed from cast iron. Cast iron conducts heat at a much lower rate than aluminium. This means that combustion temperatures are generally much higher than in aluminium engines.
All are indirect injection. This means that a smaller amount of unburnt fuel enters the cylinder where it can cause damage. Unburnt fuel remains in the combustion chamber where it will be burnt on subsequent cycles.
All Volvox engines are designs from an older generation where fuel specifications were less strict. Manufacturers of the original designs built their engines to cope with fuel specification variance.

Volvox generators have been modified (depending on the fuel required) to deal with higher viscosity fuels:-

The conversion kits include passive and self-regulating electric heaters that reduce the fuel's viscosity by raising its temperature.
The GenStation uses a pintle injector which produces a spray pattern that is more accommodating of higher viscosity fuels and has a self-cleaning characteristic.
In some cases injector release pressures have been increased.
In some models the injector timing has been advanced to allow more time to burn lower Cetane value fuels.

What fuels (and fuel blends) can be used with Volvox Generators

All Volvox generators will run unmodified on regular diesel, red diesel, biodiesel and kerosene. A lubricity enhancer (such as vegetable oil) is required for prolonged use of kerosene.

Once higher viscosity fuel modifications/kits have been added to Volvox generators, they can still use the above fuels, without ay deleterious effects.

Kerosene is less viscous than regular diesel so is very useful for blending with higher viscosity fuels like waste vegetable oil and waste motor oil. Paraffin is also good in this role.

Waste motor oil should never be used as a sole fuel in Volvox Generators. Motor oil has been designed to have a stable (high) viscosity even at high temperatures. The best way to improving its burning ability is to blend it with a lower viscosity fuel such as kerosene. We also recommend that Waste Motor Oil be blended with a 3% proportion of acetone. Acetone has the effect of reducing the surface tension of the waste motor oil, making the blend easier to spray by the injector.

[N.B. There are regulations against the use of waste motor oil as a fuel. They are probably based on the fact that the additives in these oils cause the creation of toxic chemicals in the exhaust when burnt by an engine. If you do decide to use WMO as a fuel, please deal with the exhaust gases responsibly.]

It is also possible to burn oils that are solid at room temperature in Volvox generators. However, it is mandatory that a dual fuel system is implemented so that the engine starts and stops on a more traditional fuel. Volvox do not provide components for dual fuel systems, but there are many suppliers in the 'alternative fuel for automotive' that provide the necessary components.

We recommend that biodiesel is used periodically in your Volvox generator, as this is very good at cleaning the fuel system.

What methods can be used to prepare waste vegetable oil for burning in a Volvox Generator

There are three fundamental methods of preparing your fuels for use in Volvox generators:- Passive Filtering, Passive Settling and Active Filtering.

Passive Filtering

Filtering waste vegoil

This method uses the force of gravity to push the fuel through some filtering medium. Many different materials can be used - from dairy industry filter bags to old jeans, tights or t-shirts. Some commercially available products are available here.

The diagram below shows the basic principle of suspending a filter bag within the fuel container - putting the fuel in at one side of the filter and taking it out at the other. In this particular example, a pillow case would work well.

Passive Settling

As in the above method, Passive Settling uses gravity to do the work for us.
The principle is based on the fact that, given enough time, most (there are some exceptions - see below) of the unwanted particulates in your waste vegetable oil will be pulled to the bottom of your fuel container by gravity, leaving clean fuel above. The diagram below shows a typical setup.

waste oil settling

Active Filtering

centrifugal oil filter

If you get yourself an appropriate powered oil pump, you can clean your fuel through a variety of filters. Centrifugal filters are the best as you don't need to continually replace the filters and if you get the pressure and flow rate correct you filter down to 1 micron. Commercially available units are available from here, or here.

Alternatively, you can get yourself something from your local scrap-yard, such as a power steering pump, and drive it from your engine, or a 12volt hydraulic pump for driving the hood/roof on some convertible roof cars.

Of course, any of the above methods could be combined. It really depends on the quality of your raw fuel.

Also, the sizes and number of preparation containers is a function of the quantity of fuel you consume and how dirty it is.

For more information about preparing your fuel, take a look here.

Where can I get vegetable oil to fuel my Volvox Generator

The cheapest sources of waste vegetable are your local pubs and restaurants. Prices will vary and are negotiable, and you will of course have to do the filtering/settling yourself.

If you prefer not to have to collect and prepare your fuel we strongly recommend that you contact your local biodiesel manufacturer and ask them to sell you their filtered waste vegetable oil (i.e. before they've converted it into biodiesel). We use Golden fuels (Oxfordshire), but you can find your local supplier here.

Farms

Vegetable oil goes through seven process stages to get to food grade. Each stage has an associated cost which adds to the price of the oil. The Volvox engines do not care about any of these stages except the first - the filtration stage. Buying direct (from the farm and/or the processing plant) would be the cheapest source of new vegetable oil.

We have heard that there are now Farmers offering cold-pressed Rapeseed Oil, in IBCs. We are very keen to support this initiative but don't yet have any identified suppliers. If you are a farmer wishing to sell straight vegetable oil directly, or you know of such a farmer, please send us the details and we will publish advertise them here.

National Oil Collection companies

There are several national oil collection companies that are offering filtered waste oil. Arrow Oils is one example.