Here are some more details along with the research we did with Cummins QuickServe on this:
Here are the details direct from Cummins QuickServe:
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Diesel Fuel
Diesel fuel performs three major functions in a Cummins® diesel engine.
It supplies all the energy for the engine.
It cools and lubricates the precision parts of the engine's fuel pump and injectors.
It enables emissions controlled engines to meet regulated emissions levels.
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Fuel Cleanliness
This section explains the importance of fuel cleanliness to the successful operation of Cummins® Engines.
Modern fuel systems have been developed to reduce emissions and fuel consumption, and improve engine performance. These high pressure systems operate at pressures approaching 2100 bar [30,500 psi] and with component match clearances typically from 2 to 5 microns for injectors. At these pressures, very small, hard particles are potential sources of fuel system malfunction.
Excessive contamination of diesel fuel can cause premature clogging of diesel fuel filters and/or premature wear of critical fuel injection system parts. Depending on the size and nature of the particles, this can lead to:
Reduced component life.
Component malfunction.
Fuel system and/or engine failure.
Determining fuel cleanliness requires measuring both the size and number of particles per size class in the fuel, i. e. the particle size distribution. The International Standards Organization (ISO) has developed a protocol for expressing the level of contamination by coding the size distribution called
ISO 4406.
ISO 4406 cleanliness codes are expressed as a series of three numbers (x/x/x), which correspond respectively to the number of particles greater than 4, 6, and 14 microns. For example, the numbers in the ISO 4406 rating of 18/16/13 translate to:
18 - Up to 2,500 particles larger than 4µm (per mL of fuel)
16 - Up to 640 particles larger than 6µm (per mL of fuel)
13 - Up to 80 particles larger than 14µm (per mL of fuel)
Engine builders and fuel injection equipment manufacturers have found that the particles greater than 4 microns and greater than 6 microns are particularly critical to the durability of the fuel injection system. They also recognize that the fuel systems must tolerate hard particles smaller than 4 microns that are difficult to filter out, even with the finest filtration. To maximize the efficiency and effectiveness of filtration,
Cummins Inc. has adopted the recommendation of the World Wide Fuel Charter that fuel supplied to engines meet the ISO 4406 code of 18/16/13 maximum for respectively 4, 6, and 14 micron particle sizes.
Cummins Inc. recommends that if the fuel does not meet the ISO cleanliness code of 18/16/13 when supplied to the engine, additional filtration be applied before the fuel is delivered to the equipment's fuel tank. A Cummins® Distributor or Cummins Filtration™ representative can supply hardware and additional filtration guidance and can recommend countermeasures such as improved fuel quality from the fuel supplier, and/or better fuel handling, storage, dispensing, and fuel tank cleaning techniques.
https://quickserve.cummins.com/qs2/pubsys2/xml/en/bulletin/3379001.html
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