To reduce emissions from diesel engines, especially nitrogen oxides (NOx), selective catalytic reduction (SCR) and exhaust gas recirculation (EGR) technologies are used. SCR requires a high-quality diesel exhaust fluid (DEF), also known as AUS 32 & AUS 40 (aqueous urea solution), to treat exhaust gases and remove harmful pollutants, especially nitrogen dioxide (NO2).
AUS 32 consists of a high purity 32.5% solution of urea in water and is stored in its own tank in the car. Whereas AUS 40 consists of high purity 40% solution of urea in water and applicable for marine engine and boiler exhaust. Its widespread introduction coincided with the current Euro 6 emissions standards, which are part of ever more stringent emissions targets that diesel engine manufacturers are now required to meet.
The “AdBlue” trade name, which is registered by the German car manufacturers association (Verband der Automobilindustrie, VDA). VDA issues licenses to any manufacturers of AUS 32 wishing to use the trade name AdBlue. However, to maintain the quality of AdBlue, all licensees must adhere to ISO 22241 and ISO 18611 standards.
CCIC Singapore provides the following tests in accordance with ISO-22241-2(AUS32) & ISO-18611(AUS40) standards.
ISO-22241-2(AUS32)
| No | Test Item | Unit | Limit | Method |
|---|
| 1 | Urea Content | % mass | 31.8-33.2 | ISO 22241-2 Annex B
ISO 22241-2 Annex C |
| 2 | Refractive Index (nD20) | – | 1.3814-1.3843 | ISO 22241-2 Annex C |
| 3 | Alkalinility as NH3 | % mass | 0.2 Max | ISO 22241-2 Annex D |
| 4 | Biuret | % mass | 0.3 Max | ISO 22241-2 Annex E |
| 5 | Aldehydes | mg/kg | 5.0 Max | ISO 22241-2 Annex F |
| 6 | Insoluble matter | mg/kg | 20 Max | ISO 22241-2 Annex G |
| 7 | Phosphate (PO4) | mg/kg | 0.5 Max | ISO 22241-2 Annex I |
| 8 | Aluminium | mg/kg | 0.5 Max | ISO 22241-2 Annex I |
| 9 | Calcium | mg/kg | 0.5 Max | ISO 22241-2 Annex I |
| 10 | Chromium | mg/kg | 0.2 Max | ISO 22241-2 Annex I |
| 11 | Copper | mg/kg | 0.2 Max | ISO 22241-2 Annex I |
| 12 | Iron | mg/kg | 0.5 Max | ISO 22241-2 Annex I |
| 13 | Potassium | mg/kg | 0.5 Max | ISO 22241-2 Annex I |
| 14 | Magnesium | mg/kg | 0.5 Max | ISO 22241-2 Annex I |
| 15 | Sodium | mg/kg | 0.5 Max | ISO 22241-2 Annex I |
| 16 | Nickel | mg/kg | 0.2 Max | ISO 22241-2 Annex I |
| 17 | Zinc | mg/kg | 0.2 Max | ISO 22241-2 Annex I |
ISO-18611(AUS40)
| No | Test Item | Unit | Limit | Method |
|---|
| 1 | Urea Content | % mass | 39.0-41.0 | ISO 18611-2 Annex B
ISO 18611-2 Annex C |
| 2 | Density @ 20°C | kg/m3 | 1105-1177 | ISO 12185 |
| 3 | Refractive Index (nD20) | – | 1.3947-1.3982 | ISO 18611-2 Annex C |
| 4 | Insoluble matter | mg/kg | 50 Max | ISO 18611-2 Annex G |
| 5 | Alkalinity as NH3 | % mass | 0.5 Max | ISO 18611-2 Annex D |
| 6 | Biuret | % mass | 0.8 Max | ISO 18611-2 Annex E |
| 7 | Aldehydes | mg/kg | 100 Max | ISO 18611-2 Annex F |
| 8 | Phosphate (PO4) | mg/kg | 1.0 Max | ISO 22241-2 Annex I |
| 9 | Calcium | mg/kg | 1.0 Max | ISO 18611-2 Annex I |
| 10 | Iron | mg/kg | 1.0 Max | ISO 18611-2 Annex I |
| 11 | Potassium | mg/kg | 1.0 Max | ISO 18611-2 Annex I |
| 12 | Magnesium | mg/kg | 1.0 Max | ISO 18611-2 Annex I |
| 13 | Sodium | mg/kg | 1.0 Max | ISO 18611-2 Annex I |
| 14 | Identity | – | Pass | ISO 18611-2 Annex J |