| |
Summary of Effect of Diesel Fuel Quality on Emissions
Effect of changes in important diesel fuel properties on CO, HC, NOx and PM emissions has been investigated in several programmes in Europe and the USA and also by other investigators. The overall effects of fuel properties on emissions are qualitatively summarized in Table 8.11.
| Table 8.11 |
| Summary of Overall Effects of Diesel Fuel Property Changes on Emissions |
Vehicle type |
Fuel Property |
Property Change |
CO |
HC |
NOx |
PM |
Light-duty vehicles |
Increase CN
Reduce density
Reduce T95
Reduce PAH
Reduce sulphur |
50 → 55
850 → 820 kg/m3
370 → 330 C
6 → 3 % v/v
2000 →500 ppm |
↓↓
↓
-0
?
0 |
↓↓
↓
-0
?
0 |
±0
0
-0
?
0 |
↓
↓↓↓
-0
?
↓ |
Heavy-duty vehicles |
Increase CN
Reduce density
Reduce T95
Reduce PAH
Reduce sulphur |
50 → 55
850 → 820 kg/m3
370 → 330 C
6 → 3 % v/v
2000 →500 ppm |
↓
0
-0
?
0 |
↓
0
-0
?
0 |
↓
↓
-0
?
0 |
↓
↓
-0
?
↓↓ |
| Key: 0 = No effect; ± 0 = -2 to 2 %; ↓ or ↑ = 2 to 10%; ↑↑ or ↓↓ = 10 to 20%; ↑↑↑ or ↓↓↓ = >20%; ? = Insufficient data |
Diesel Fuel Specifications
Engine technology is being continuously modified and upgraded to meet the newer and more stringent emission regulations. Accordingly, the diesel fuel quality also has undergone significant improvements particularly related to CN, sulphur content, tail end volatility and wear protection of injection system. In some countries, bio-diesel is also being blended with diesel fuel. To keep injection pump calibration at acceptable level with diesel-fuel and biodiesel blends, a maximum oxygen content limit has been specified in the Indian fuel specifications. The key diesel fuel properties in Europe and India are given in Table 8.12.
| Table 8.12 |
| Diesel Fuel Specifications in Some Countries |
Property |
Europe
(EN590: 1999) |
India
(IS 1460)
(BS IV - 2010) |
Cetane number, min. |
51 |
51 |
Cetane index, min |
46 |
46 |
Density @ 15º C, kg/m3 |
820-845 |
820-845 |
Viscosity @40º C, mm2/s |
2.0 -4.5 |
2.0-5.0 |
Sulphur, %m/m, max. |
0.035 |
BS III: 0.035
BS IV: 0.005 |
Total aromatics, % m/m, max. |
|
- |
Polyaromatics, (di+tri++), max. |
11 |
11 |
Distillation: |
|
|
% recovered at 250º C, max. |
65 |
|
T 85, ºC, max. |
350 |
|
T90, ºC, max./range |
|
- |
T95, ºC, max. |
360 |
360 |
FBP, ºC /range |
- |
- |
Flash Point, ºC, min. |
55 |
35 |
Carbon residue, % m/m, max. |
0.30 |
0.30 |
Water content, mg/kg, max. |
200 |
200 |
Oxidation stability g/m3, max. |
25 |
25 |
Particulates, mg/l |
24 |
- |
Lubricity(HFRR scar dia. @ 60º C), µm |
460 |
460 |
Oxygen content, % by mass max. |
- |
0.6 |
|
