Engines Require Clean Diesel

 

The pressure generated by a common-rail system is roughly equivalent to the pressure a 2,000-kilogram rhinoceros would exert standing on a fingernail. The compressed fuel is then finely dispersed at the speed of a supersonic jet."
 
Bosch
Pressure in diesel engines
11 November, 2013 
Engines Need Clean Fuel 

In order to produce cleaner, more efficient engines, manufacturers have been obliged to make dramatic changes to fuel systems. These efforts have been successful, as engines today burn clean and produce much less air pollution than in the past. In addition, more dangerous emissions are now removed by exhaust after treatment devices. Success comes with a price; these new engines are extremely precise pieces of engineering and for proper functionality, require equally precise control of the fuel that is put into them. 
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All engines benefit from clean fuel with extended parts life and increased uptime, but modern engines must have spotlessly clean fuel at all times. 
Poor handling practices or failure to pay vigilant attention to fuel cleanliness can otherwise have disastrous results. 
 
HIGH PRESSURE COMMON RAIL INJECTORS 
combustion
High pressure common rail engines operate at up to 40,000 psi (2750 bar), compared to under 5000 psi (345 bar) only a few years ago. 

The trend toward even higher pressures will continue. System pressures of 60,000 psi (4000 bar) and more are predicted. In order to operate at such high pressure, fuel systems need to be extremely precise. Orifice sizes, clearances and tolerances can be as small as 1 micron, 40 times smaller than the human eye can see. Even tighter tolerances will be required as internal fuel system pressures continue to increase. 

pump and injector
Precision devices are not forgiving, even low levels of contamination can cause catastrophic failure. In fact, it is the smallest 1-5 micron particles that cause the worst damage. These high pressure environments create 
a virtual water jet cutter inside the fuel system. Microscopic contaminants bombard metal parts at high speeds, causing pitting, scoring and erosion 
of injectors and fuel pumps. Reduced part lifetimes, part malfunction and increased exhaust emissions are frequently observed. Subsequent loss of pressure or over or under fueling can eventually lead to complete engine failure. 

HIGH PRESSURE FUEL PUMPS 
The fuel pump which directly feeds fuel to the common rail is also subject 
to high pressure and susceptible to damage by microscopic contaminants. These high pressure pumps must be extremely precise to provide the exact quantity and timing of fuel needed by injectors. Sticky deposits and loss of pressure from abrasive wear or water corrosion can cause inefficient function or complete failure. 

HPCR FILTRATION REQUIREMENTS 
In order to avoid damage from hard and soft contaminants, diesel fuel must be microscopically clean. This cannot be accomplished with traditional fuel filters. Only high efficiency filters made from sophisticated synthetic media can achieve the level of cleanliness required by modern fuel systems. A good secondary fuel filter should remove contaminants down to 2 microns and below with over 99% efficiency. One side effect of such high efficiency is that these filters catch a great deal of contaminant. They must, in order to protect the engine. The consequence, however, is that they may require more frequent service intervals than less efficient filters. A filter that lasts "forever" is not preventing harmful contaminants from entering the engine. 

These high efficiency filters are specified by OE's to protect HPCR equipment. If you choose to use an after-market filter (i.e. a different brand), be sure that it meets or exceeds the original equipment manufacturer specifications. Just because a filter cross references does not mean that it gives equal performance. Warranty coverage may be compromised if OE specifications are not followed.