A winter’s tale
The law of unintended consequences often complicates good intentions. One example is the reduction of pollutants in diesel which has some adverse impacts on performance.
Diesel power remains a mainstay of the UK market, particularly in outside-only operations where it is often seen as cheaper and more convenient than LPG. Yet diesel is not perfect.
Jason Reynolds, director at Windsor Materials Handling explains: “For one, it is prone to waxing or gelling in cold weather. Below the Cloud Point – the temperature at which dissolved solids are no longer completely soluble – the fuel begins to develop solid wax particles. The presence of solidified waxes thickens the fuel and clogs engine filters and injectors.
“The crystals build up in the fuel line until the engine is starved of fuel, causing it to stop running.”
Efforts to meet increasingly stringent emissions standards have led to the development of ultra-low-sulphur diesel (ULSD) which may exacerbate the problem. Sulphur is a natural part of the crude oil from which diesel fuel is derived, and one of the key causes of particulates, or soot, in diesel. Last winter, Russian ULSD was suspected of causing a number of problems for motorists.
As the weather turned cold, imported fuel began to react with biofuels to create a gel-like substance, leaving the driver unable to start their car.
So should forklift users be worried? Well, while the environmental benefits of less sulphur is accepted, there are some worrying issues. Red diesel is allowed to contain higher sulphur levels, but the refining process used to reduce the sulphur level in regular diesel can also reduce the natural lubricating properties. Oil in a diesel engine not only lubricates, it cools the engine and cleans the carbon away from the pistons and the liners.
This is essential for the operation of fuel system components such as fuel pumps and injectors. As last winter proved, oil companies can also change the overall chemical composition of the fuel and they have done this to reduce the sulphur content.
Jason concludes: “The resulting mix can cause engine seals to swell or shrink, making a leak possible. Thankfully, regular servicing and the replacing of seals with newer, less susceptible materials, is the best way to stay spillage free.”
Biodiesel further complicates the picture, as BITA explains further. Biodiesel can now comprise up to 7% of UK gas oil/red diesel and as biodiesel blends can absorb more water this can precipitate out of solution when the temperature changes.
BITA’s technical consultant, Bob Hine says: “This in turn can create the conditions for microbial contamination, the ‘diesel bug’, leading to sludge problems. Biodiesel also oxidises and breaks down more easily in the presence of oxygen, creating peroxides that eventually form acids, leading to formation of gums and resins which can block fuel filters.”
{EMBED(548294)}
Fuel can also be contaminated with dirt, rust, sand etc which can result from simple bad fuel handling practices and cause real damage to an engine or machine and its fuel system.
For some engines, fuel containing the maximum 7% of biodiesel can result in reduced cold-weather handling performance and more water pick-up potential, meaning a great possibility of corrosion in filters. This has led to some suppliers offering so-called ‘FAME-free fuel’ which claims to contain no biodiesel, but this is extremely difficult for a supplier to guarantee, given the prevalence of biodiesel in the supply chain, so relying on this has potential problems.
In addition, check the grade of your fuel. Engines designed to run on ‘European’ grade diesel, with a cetane rating of 51 (the cetane number being the measure of how readily diesel burns under compression) can struggle to run effectively on UK red diesel, which has a cetane level of 45.
Windsor Materials Handling: 01482 229942
British Industrial Truck Association (BITA): 01344 623800
