How to avoid fuel injection failures

2 March 2018

Fuel injection in diesel engines takes place at very high temperatures. These temperatures break down standard diesel fuel, leaving carbon and other deposits that foul the injector and lead to reduced performance and even engine damage. Advanced fuels can protect the engine using additives that prevent fouling.

Fuel injection does what it says – injects fuel directly into an engine. All diesel engines use this technology, as do the latest petrol engines. High pressure fuel injectors are vulnerable to the formation of deposits inside the fuel injector, in the diesel meter valve, and on the nozzle of the needle.

Injector strategies for diesel engines have had to become more sophisticated because the injectors are now operating at up to 3,000 bar of pressure. Very small holes in the injector enable a micro fine spray of fuel to give very efficient combustion; however, such small holes are easily blocked by dirt or deposits. The spray is then affected, and pretty soon the engine’s combustion becomes less efficient. This generates dirt and the performance of the engine is reduced.

Many owners of agricultural and other machinery notice a diminution in performance and blame the engine; however, the cause is often fuel by-products fouling the fuel injection system (not to include in this blog but blocking of the aftertreatment system is an even more common root cause). New diesel engines have delivered a cleaner burn and lower emissions; however, used with standard diesel, the signs of injector fouling starts to become evident in lower fuel economy and loss of power(not quite true. The DPF in the exhaust system becomes blocked but not fuel filters).

The answer clearly lies in better diesel fuel that can avoid these problems while maintaining lower emissions, which is where the fuel designers come in.
Cost-effectiveness of premium fuels

Using standard diesel fuel in high-tech, high-cost equipment can be a false economy if it results in engine damage; therefore, there is a market for premium fuels (e.g. Shell V-Power, BP Ultimate) that can protect modern engines from the effect of the high temperatures needed for combustion and clean away dirt from the engine parts with which they are in contact.

These fuels have additives that prolong engine life by discouraging the deposits that cause problems for fuel injected engines. They contain detergents and anti-foulants that can prevent fuel coking and improve the lubricity of the fuel pump. At the same time, they can even enhance fuel economy.

Finding additives that can perform

The difficult part is designing the additives to work with the fuel. Fuel designers have to research, develop, test, fine tune and retest potential products. Refiners, which will sell the ultimate product to the public, then have to carry out their own testing because launching a new fuel is a costly business and one they do not carry out that often.
They have to be convinced they have a winning fuel on their hands before they bring it to market. Recent successful launches of premium fuels in Europe have demonstrated that customers are willing to pay more for fuel if it protects their engine, so refiners are looking carefully at the premium fuel proposition.
Fuel design moves rapidly because fuels have to keep up with new advances in vehicle manufacturing and find solutions to new challenges as they arise. The continuing development of advanced fuels is vital for the industry, the environment and drivers.

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