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Compare the result of the specified viscosity with the
requirements of the standard and give an opinion on the
compliance of this indicator with the specifications of the
specifications for this brand of diesel fuel.
Determination of fuel density. Fuel density is its mass
3
per unit volume; its dimension is- kg/m .
In practice, they deal with dimensionless quantities - the
relative density, which is the ratio of the density of fuel (oils) at
a given temperature to the density of water at a temperature
+4С, which is taken in the same volume. Water density at +4
3
С equals 1000 kg/m . The relative density of fuel is taken to
20
determine at +20 С and mark the symbol  .
4
Density is temperature dependent. As the temperature
increases, the density of the oil product decreases. The fuel
density can be measured at any temperature, but the
measurement result is usually related to the temperature 20 С,
which is accepted as standard in the assessment of the density
of petroleum products.
t
Knowing the density at any temperature  t  you can
determine the density at 20 С, using the formula:
 20   t   t 20 , (9.2)
t
where  – oil product density at determination temperature,
3
kg/m ; t – test temp,С;  – average temperature change of
3
density change on 1С, kg/(m К) (tabl. 9.2).

Table 9.2 - Average temperature corrections of
petroleum products
Density of the Temperatures Density of the oil Temperatures
oil is measured, on the is measured,  t, on the
3
3
 t, kg/m correction on кг/м correction on
3
3
1С, , kg/(m  1С, , kg/(m 
degree) degree)
700…709 0,897 820…829 0,738
710…719 0,884 830…839 0,725
720…729 0,870 840…849 0,712
47