Precautions to Observe for Diesel Fuel Use

The most important point in the use of diesel fuel is its cold temperature behavior. The subject has been addressed previously because it directly affects the engine operation in winter conditions. 

We will examine here other quality criteria having less impact yet still being important. 

Two criteria are used to characterize the behavior of diesel fuel in this area these are color and resistance to oxidation. 

The tendency of the color to become darker with time is often indicative of chemical degradation. The test is conducted with the aid of a colorimeter (NF T 60-104 and ASTM D 1500) and by comparison with colored glass standards. The scale varies from 0.5 to 8. The French specifications stipulate that diesel fuel color should be less than 5, which corresponds to an orange-brown tint. Generally, commercial products are light yellow with indices from 1 to 2. 

The procedure most commonly employed (NF M 07-047 or ASTM D 2274) Is to age the diesel fuel for 16 hours while bubbling oxygen into it at 95°C. The gums and sediment obtained are recovered by filtration and weighed. There is no official French specification regarding oxidation stability however, in their own specifications, manufacturers have set a maximum value of 1.5 mg/100 ml. 

---