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]. Since the Euro 5/6 stage, the reference fuel contains 5% FAME biodiesel, Table 1.3 [Regulation 692/2008].

Reference fuel specifications for heavy-duty diesel engines at the Euro III, Euro IV and Euro V stages are listed in Table 1.4 [Directive 2005/55/EC]. The proposed specification for Euro VI, which introduces a 7% FAME content, is summarized in Table 1.5.

Table 1.1
98/69/EC (Euro 3) & 99/96/EC (Euro III) Reference Diesel Fuel
Cetane Number 5254ISO 5165
Density @15°Ckg/m3833837ISO 3675
Distillation (vol. % recovered)°C  ISO 3405
  - 50% point245-
  - 95% point345350
  - final boiling point-370
Flash point°C55-EN 22719
CFPP°C--5EN 116
Viscosity @40°Cmm2/s2.53.5ISO 3104
Polycyclic aromatic hydrocarbons% wt.3.06.0IP 391, EN 12916
Sulfur contentamg/kg-300*ISO/DIS 14596
Copper corrosion -Class 1ISO 2160
Conradson carbon residue (10% DR)% wt.-0.2ISO 10370
Ash content% wt.-0.01ISO 6245
Water content% wt.-0.05ISO 12937
Neutralization (strong acid) numbermg KOH/g-0.02ASTM D974-95
Oxidation stabilitymg/ml-0.025ISO 12205
* sulfur limit of 50 mg/kg effective 2005 (Euro 4)
a - the actual sulfur content must be reported

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 [Directive 2004/26/EC, Directive 2010/26/EC].

Table 2.1
EU Stage I/II Nonroad Reference Diesel Fuel
Cetane Number 4550ISO 5165
Density @15°Ckg/m3835845ISO 3675, ASTM D4052
Distillation, 95% v/v recovered°C-370ISO 3405
Viscosity @40°Cmm2/s2.53.5ISO 3104
Sulfur% wt.0.10a0.20bEN 24260, ISO 8754
Flash Point°C55-IO 2719
CFPP°C-+5°CEN 116
Copper corrosion -Class 1ISO 2160
Conradson carbon residue (10% DR)% wt.-0.3ISO 10370
Ash% wt.-0.01ISO 6245
Water content% wt.-0.05ASTM D95, D1744
Neutralization (strong acid) numbermg KOH/g-0.20ASTM D974
Oxidation stabilitymg/100 ml-2.5ASTM 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.