EU: Fuels: Reference Fuels
Road Vehicles
Specifications for reference (certification, homologation) fuels for both light-duty [Directive 1998/69/EC] and heavy-duty vehicles [Directive 1999/96/EC] introduced a sulfur limit of 300 ppm effective year 2000 (Euro 3) and 50 ppm from 2005 (Euro 4), Table 1.1.
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In October 2002, the sulfur specification for Euro 4 type approvals of light-duty vehicles was lowered to 10 ppm, Table 1.2 [Directive 2002/80/EC]. Starting with the Euro 5/6 stage, the reference fuel contains 5% FAME biodiesel, Table 1.3 [2764]. Other reference fuels specified for Euro 6 vehicles include E5 gasoline, E85, LPG and natural gas/biomethane. There is also an E5 reference fuel for emission testing at low ambient temperatures.
Reference fuel specifications for heavy-duty diesel engines at the Euro III, Euro IV and Euro V stages are listed in Table 1.4 [1569]. The specification for Euro VI introduced a 7% FAME content [3494]. Table 1.5 summarizes the Euro VI reference fuel specification updated in 2014 [6256]. Note that Euro VI and Euro 6 diesel reference fuels are not the same. Other reference fuels specified for Euro VI engines include B100, ethanol for dedicated compression-ignition engines (ED95), E10 gasoline, E85, LPG and natural gas/biomethane.
Euro VI includes a universal fuel range requirement. For diesel engines, if a manufacturer permits an engine family to run on market fuels other than diesel fuel or B100, type-approval emission limits must be met with the fuels declared and ISC emission limits with any blend of the declared fuels and market fuels included in the Fuel Quality Directive [6205].
| Property | Unit | Specification | Test | |
|---|---|---|---|---|
| Min | Max | |||
| Cetane Number | 52 | 54 | ISO 5165 | |
| Density @15°C | kg/m3 | 833 | 837 | ISO 3675 |
| Distillation (vol. % recovered) | °C | ISO 3405 | ||
| - 50% point | 245 | - | ||
| - 95% point | 345 | 350 | ||
| - final boiling point | - | 370 | ||
| Flash point | °C | 55 | - | EN 22719 |
| CFPP | °C | - | -5 | EN 116 |
| Viscosity @40°C | mm2/s | 2.5 | 3.5 | ISO 3104 |
| Polycyclic aromatic hydrocarbons | % wt. | 3.0 | 6.0 | IP 391, EN 12916 |
| Sulfur contenta | mg/kg | - | 300* | ISO/DIS 14596 |
| Copper corrosion | - | Class 1 | ISO 2160 | |
| Conradson carbon residue (10% DR) | % wt. | - | 0.2 | ISO 10370 |
| Ash content | % wt. | - | 0.01 | ISO 6245 |
| Water content | % wt. | - | 0.05 | ISO 12937 |
| Neutralization (strong acid) number | mg KOH/g | - | 0.02 | ASTM D974-95 |
| Oxidation stability | mg/ml | - | 0.025 | ISO 12205 |
| * sulfur limit of 50 mg/kg effective 2005 (Euro 4) a - the actual sulfur content must be reported | ||||
| Property | Unit | Euro 3 | Euro 4 | Test | ||
|---|---|---|---|---|---|---|
| Min | Max | Min | Max | |||
| Cetane Number | 52 | 54 | 52 | 54 | ISO 5165 | |
| Density @15°C | kg/m3 | 833 | 837 | 833 | 837 | ISO 3675 |
| Distillation (vol. % recovered) | °C | ISO 3405 | ||||
| - 50% point | 245 | - | 245 | - | ||
| - 95% point | 345 | 350 | 345 | 350 | ||
| - final boiling point | - | 370 | - | 370 | ||
| Flash point | °C | 55 | - | 55 | - | EN 22719 |
| CFPP | °C | - | -5 | - | -5 | EN 116 |
| Viscosity @40°C | mm2/s | 2.5 | 3.5 | 2.3 | 3.3 | ISO 3104 |
| Polycyclic aromatic hydrocarbons | % wt. | 3.0 | 6.0 | 3.0 | 6.0 | IP 391 |
| Sulfur contenta | mg/kg | - | 300 | - | 10 | ASTM D5453b |
| Copper corrosion | - | 1 | - | 1 | ISO 2160 | |
| Conradson carbon residue (10% DR) | % wt. | - | 0.2 | - | 0.2 | ISO 10370 |
| Ash content | % wt. | - | 0.01 | - | 0.01 | ISO 6245 |
| Water content | % wt. | - | 0.02 | - | 0.02 | ISO 12937 |
| Neutralization (strong acid) number | mg KOH/g | - | 0.02 | - | 0.02 | ASTM D974 |
| Oxidation stability | mg/ml | - | 0.025 | - | 0.025 | ISO 12205 |
| Lubricityc | µm | - | - | - | 400 | CEC F-06-A-96 |
| FAMEd | - | - | Prohibited | |||
| a - the actual sulfur content must be reported b - Pr. EN-ISO/DIS 14596 at the Euro 3 stage c - HFRR wear scan diameter at 60°C d - fatty acid methyl ester (biodiesel) | ||||||
Nonroad Vehicles
Specifications for reference diesel fuel for the type approval and conformity testing of Stage I/II nonroad mobile diesel engines are listed in Table 2.1 [Directive 97/68/EC].
Reference fuel specifications for Stage III/IV testing are listed in Table 2.2 [2906][6257].
Stage V reference fuel is summarized in Table 2.3 [6258]. FAME up to 7% is allowed.
| Property | Unit | Specification | Test | |
|---|---|---|---|---|
| Min | Max | |||
| Cetane Number | 45 | 50 | ISO 5165 | |
| Density @15°C | kg/m3 | 835 | 845 | ISO 3675, ASTM D4052 |
| Distillation, 95% v/v recovered | °C | - | 370 | ISO 3405 |
| Viscosity @40°C | mm2/s | 2.5 | 3.5 | ISO 3104 |
| Sulfur | % wt. | 0.10a | 0.20b | EN 24260, ISO 8754 |
| Flash Point | °C | 55 | - | IO 2719 |
| CFPP | °C | - | +5°C | EN 116 |
| Copper corrosion | - | Class 1 | ISO 2160 | |
| Conradson carbon residue (10% DR) | % wt. | - | 0.3 | ISO 10370 |
| Ash | % wt. | - | 0.01 | ISO 6245 |
| Water content | % wt. | - | 0.05 | ASTM D95, D1744 |
| Neutralization (strong acid) number | mg KOH/g | - | 0.20 | ASTM D974 |
| Oxidation stability | mg/100 ml | - | 2.5 | ASTM D2274 |
| Additivesc | Not allowed | |||
| a - engines with no exhaust gas aftertreatment can be approved using 0.05% S fuel, in which case PM emissions are corrected upward by calculation. Production conformity testing must be conducted using fuel of 0.10-0.20% S level. b - higher values are permitted, in which case the sulfur level must be reported. c - fuel should be based on straight run and cracked hydrocarbon distillate. Desulfurization is allowed. Metallic or cetane improver additives are not allowed. | ||||