Fuel filtration is an integral part of the complete fuel system. Modern engines are increasingly requiring better fuel filtration technology to ensure delivery of the cleanest fuel to your engine’s fuel system, as contaminated fuel can lead to vehicle downtime and costly repairs to your engine and expensive fuel system components. Donaldson answers some common questions on ensuring adequate fuel filtration and system protection.
Q: Where should I install additional filtration?
A: We recommend that additional filtration should be considered as the primary filter and installed before the factory filter, which should be retained as originally fitted. It can be fitted in any location that offers easy access to view the water collection bowl and to change the filter. Most modern vehicles employ a return loop fuel system, where fuel is delivered to the factory fitted filter. The engine draws what it requires and the rest is returned to the tank. By installing additional filtration before the factory filter, all the fuel in the tank is being continually filtered. Leaving the fuel system from the factory filter to the engine unaltered, minimising any effect on sensitive engine management systems. This also ensures the fuel reaching the factory fitted filter is as clean as the vehicle manufacturer specifies.
Q: Do I need to add additional filtration?
A: If you operate your vehicle in remote locations, or anywhere that the quality of the available fuel is uncertain, the use of additional fuel filtration is a great way to prevent fuel related issues.
Q: What else do I need to install additional filtration?
A: Some vehicles can benefit from additional in-line fuel pump to help boost the fuel flow. Use a good quality pump for reliable and long life.
Q: Are there any points to consider when installing an additional filter?
A: The additional filter needs to be capable of delivering an adequate fuel flow rate for your engine. Ensure there are no tight bends in the fuel lines and do not position them too close to hot exhaust components. All fuel hose connections need to be fuel and air tight. It is good practice to use a fuel-proof thread sealant on hose fittings where they screw into the filter head assembly. Many fuel systems operate in vacuum. A leak may result in air being drawn into fuel lines causing engine misses or making it hard to start.
Q: I've been handling diesel the same way for years without any issues, why should I change what I am doing?
A: Depends on what you're driving. If you drive an older technology (pre-common rail) vehicle, then you can probably continue to do what you've always done. However, if you have a newer technology (such as a common rail) vehicle, or are planning to get one then you will have to be more careful with where and how you refuel.
If your vehicle has suffered from premature fuel system failures, please read-on.
Q: What has changed with diesel fuel to cause these fuel system failures?
A: With the exception of reducing the sulphur content, fuel standards have not changed substantially in over a decade. The supply of perfectly in-spec diesel simply isn't enough any more. Poorly maintained site infrastructures, inappropriate fuel handling and service procedures may result in greater amounts of contamination in your fuel than can be tolerated by new equipment.
Q: Why have fuel systems on vehicles changed?
A: Manufacturers of modern diesel have adopted a variety of new technologies to achieve the requirements of ever tightening emissions regulations. One technology that has been commonly utilised by light vehicle manufacturers is the High Pressure Common Rail (HPCR) fuel system. HPCR fuel systems frequently operate at pressures in excess of 30,000 psi.
Q: What are the benefits of a High Pressure Common Rail fuel system?
A: Reduced emissions, improved fuel economy and greater power output and reduced engine noise.
Q: Do HPCR fuel systems have different fuel requirements than older vehicles?
A: New HPCR systems are much less tolerant of contamination in fuel as a result of the increased operating pressures. Fuel system manufacturers are insistent that damage caused by fuel contaminants is not a factory defect and in many cases is not warrantable.
Hard particulate causes irreversible damage to the moving pats and seal surfaces of a fuel system. The first signs of wear are commonly hard to start faults and rough idling. Poor engine performance including increased fuel consumption, loss of power and increased emissions are common signs of advanced wear. Catastrophic failure of fuel injectors, pumps or even complete engines may be the end result.
Q: What type and size of contamination leads to irreversible wear?
A:The precise distribution, quantity and timing of fuel delivered by high pressure common rail injectors is critical for complete combustion, performance and engine longevity. The smallest hard and soft particles, those in the size range of 1 to 5 microns are known to cause damage, pitting critical surfaces. Fuel at extreme pressure then erodes these pitted surfaces resulting in irreversible wear.
