Biodiesel is suitable for most Valtra tractors

10.01.2006

Biodiesel is produced mainly from rapeseed and soybeans, but it can also be made from other plant oils. What is essential is that the cold pressed plant oil is esterified. Esterification is a chemical process in which ten percent methanol and other additives are mixed with the plant oil, after which the mixture is heated. The esterification process separates heavier glycerine, around 8 percent, which does not burn as well. At the same time, methanol creates around 10 percent liquid oxygen in the biodiesel.

In the esterification process, the viscosity of plant oil decreases by around a quarter to a thickness similar to diesel oil, and its distillation temperature drops from over 500 degrees to around 360 degrees, similar to that of diesel oil.

Esterification makes it possible for cold pressed plant oils to be used as fuel in the SisuDiesel engines that power Valtra tractors. Without esterification, cold pressed plant oil is not suitable for use as fuel in Valtra tractors.

Biodiesel mixed or straight

Biodiesel can be used in Valtra and Valmet tractors without modifications as a 100-0 percent mix with normal diesel fuel or on its own. Normal diesel fuel fulfils EN 590 norms.

If biodiesel is used, the engine oil and fuel filter must be changed twice as often as required by the normal service interval when used with normal diesel fuel. In addition, SisuDiesel recommends that a separate water filter or prefilter be fitted between the fuel tank and engine, as biodiesel is more liable to absorb condensed water than normal diesel fuel.

Biodiesel can also corrode painted surfaces, plastics and rubber, so extra caution should be taken when filling the fuel tank. Biodiesel degrades naturally, so any overflow can be simply rinsed off.

The power output of engines using biodiesel is within three percent of that when using diesel fuel, as its greater viscosity offsets the lower combustion temperature. Engine emissions, including smoke, particles and carbon dioxide and carbon monoxide, are halved, but nitrogen oxide emissions increase by 3-10 percent. A pleasant benefit is that biodiesel fumes smell like cooked food.

Biodiesel does not keep as well as normal diesel fuel. Generally, biodiesel should not be stored for more than one year. The freezing point of biodiesel is around minus-13 Celsius, so in colder conditions it should be mixed with normal diesel fuel.

The suitability of biodiesel in new Common Rail engines that meet Tier 3 emissions standards is currently being tested. For the time being, biodiesel should only be used in these engines as a five-percent mix.

If you use biodiesel that fulfils EN 14214 norms or diesel that fulfils EN 590 norms, the warranty on your tractor and engine is valid as normal. If any other fuel is used in the tractor, the owner is responsible for possible problems.  

  

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