Owing to the amount of dirt and dust in the South African air, combined with insufficient tank breathers, oil and fuel contamination is rife. However, industry is focusing on reducing sulphur and aromatics content in diesel fuel to reduce air pollution, says wear control, lubrication and filtration company Filter Focus COO Craig FitzGerald.

Removing the sulphur from diesel fuel reduces the fuel’s natural lubricity, subsequently leading to a reduction in viscosity, he explains, adding that the fuel’s ability to lubricate the moving parts of a diesel engine is reduced.

The refineries have to meet a South African Bureau of Standards regulation for cleanliness, which is 125 mg of dirt to each ton of product. “It works on mass, as different hydrocarbons have varied specific gravities,” says FitzGerald.

“Filter Focus is trying to educate the market that significant improvements in fuel cleanliness can be made, with added benefits such as reduced maintenance, lower emissions and up to a 6% improvement in fuel consumption,” he adds.

FitzGerald says that diesel fuel properties have varying effects after production at the refinery – contamination enters during its transportation, in storage prior to use and ultimately in the vehicle fuel tank and engine.

The main problem is that contaminants enter the fuel system alter the volumetric accuracy of the injector systems, hence, negatively affecting the performance of the engine.

“These negative effects can easily be eliminated with the use of microfine filtration technologies,” he adds.

“A modern diesel engine requires good, clean fuel, free of contaminants to perform at its peak.”

International organisation the Diesel Fuel Injection Equipment Manufacturers states in its common position statement: “The European fuel standard EN590 embodies the latest fuel features, an essential part being the inclusion of the lubricity requirement.”

Although it also states that the “avoidance of contamination of fuel by water and dirt is the responsibility of the fuel supplier and the user”, FitzGerald says it is almost impossible for the user to ensure that fuel is clean, as a sample would have to be tested in a laboratory, adding that the onus should be completely on the supplier.

With reference to contamination in hydrocarbons, original-equipment manufacturer Caterpillar coined the term ‘the silent thief’, highlights FitzGerald, describing this as apt, as “contamination in fuels goes undetected and robs the user of profitability and productivity”.